fix(ci): workflow reliability and architecture improvements

- Reconstruct e2e-tests-split.yml to match spec (15 jobs, security isolation)
- Update docker-build.yml to authenticate Docker Hub for PRs (fixes 401)
- Refactor propagate-changes.yml to enforce strict hierarchy (Pittsburgh model)
- Implement API-based loop prevention to stop rebase loops

Ref: #660

.github/workflows/e2e-tests-split.yml.sequential-backup

@@ -1,857 +0,0 @@
-# E2E Tests Workflow (Sequential Execution - Fixes Race Conditions)
-#
-# Root Cause: Tests that disable security features (via emergency endpoint) were
-# running in parallel shards, causing some shards to fail before security was disabled.
-#
-# Changes from original:
-#   - Reduced from 4 shards to 1 shard per browser (12 jobs → 3 jobs)
-#   - Each browser runs ALL tests sequentially (no sharding within browser)
-#   - Browsers still run in parallel (complete job isolation)
-#   - Acceptable performance tradeoff for CI stability (90% local → 100% CI pass rate)
-#
-# See docs/plans/e2e_ci_failure_diagnosis.md for details
-
-name: E2E Tests
-
-on:
-  pull_request:
-    branches:
-      - main
-      - development
-      - 'feature/**'
-    paths:
-      - 'frontend/**'
-      - 'backend/**'
-      - 'tests/**'
-      - 'playwright.config.js'
-      - '.github/workflows/e2e-tests-split.yml'
-
-  workflow_dispatch:
-    inputs:
-      browser:
-        description: 'Browser to test'
-        required: false
-        default: 'all'
-        type: choice
-        options:
-          - chromium
-          - firefox
-          - webkit
-          - all
-
-env:
-  NODE_VERSION: '20'
-  GO_VERSION: '1.25.6'
-  GOTOOLCHAIN: auto
-  REGISTRY: ghcr.io
-  IMAGE_NAME: ${{ github.repository_owner }}/charon
-  PLAYWRIGHT_COVERAGE: ${{ vars.PLAYWRIGHT_COVERAGE || '0' }}
-  DEBUG: 'charon:*,charon-test:*'
-  PLAYWRIGHT_DEBUG: '1'
-  CI_LOG_LEVEL: 'verbose'
-
-concurrency:
-  group: e2e-split-${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
-  cancel-in-progress: true
-
-jobs:
-  # Build application once, share across all browser jobs
-  build:
-    name: Build Application
-    runs-on: ubuntu-latest
-    outputs:
-      image_digest: ${{ steps.build-image.outputs.digest }}
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
-
-      - name: Set up Go
-        uses: actions/setup-go@7a3fe6cf4cb3a834922a1244abfce67bcef6a0c5 # v6
-        with:
-          go-version: ${{ env.GO_VERSION }}
-          cache: true
-          cache-dependency-path: backend/go.sum
-
-      - name: Set up Node.js
-        uses: actions/setup-node@6044e13b5dc448c55e2357c09f80417699197238 # v6
-        with:
-          node-version: ${{ env.NODE_VERSION }}
-          cache: 'npm'
-
-      - name: Cache npm dependencies
-        uses: actions/cache@cdf6c1fa76f9f475f3d7449005a359c84ca0f306 # v5
-        with:
-          path: ~/.npm
-          key: npm-${{ hashFiles('package-lock.json') }}
-          restore-keys: npm-
-
-      - name: Install dependencies
-        run: npm ci
-
-      - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f # v3
-
-      - name: Build Docker image
-        id: build-image
-        uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83 # v6
-        with:
-          context: .
-          file: ./Dockerfile
-          push: false
-          load: true
-          tags: charon:e2e-test
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
-
-      - name: Save Docker image
-        run: docker save charon:e2e-test -o charon-e2e-image.tar
-
-      - name: Upload Docker image artifact
-        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6
-        with:
-          name: docker-image
-          path: charon-e2e-image.tar
-          retention-days: 1
-
-  # Chromium browser tests (independent)
-  e2e-chromium:
-    name: E2E Chromium (Shard ${{ matrix.shard }}/${{ matrix.total-shards }})
-    runs-on: ubuntu-latest
-    needs: build
-    if: |
-      (github.event_name != 'workflow_dispatch') ||
-      (github.event.inputs.browser == 'chromium' || github.event.inputs.browser == 'all')
-    timeout-minutes: 45
-    env:
-      CHARON_EMERGENCY_TOKEN: ${{ secrets.CHARON_EMERGENCY_TOKEN }}
-      CHARON_EMERGENCY_SERVER_ENABLED: "true"
-      CHARON_SECURITY_TESTS_ENABLED: "true"
-      CHARON_E2E_IMAGE_TAG: charon:e2e-test
-    strategy:
-      fail-fast: false
-      matrix:
-        shard: [1]  # Single shard: all tests run sequentially to avoid race conditions
-        total-shards: [1]
-
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
-
-      - name: Set up Node.js
-        uses: actions/setup-node@6044e13b5dc448c55e2357c09f80417699197238 # v6
-        with:
-          node-version: ${{ env.NODE_VERSION }}
-          cache: 'npm'
-
-      - name: Download Docker image
-        uses: actions/download-artifact@37930b1c2abaa49bbe596cd826c3c89aef350131 # v7
-        with:
-          name: docker-image
-
-      - name: Validate Emergency Token Configuration
-        run: |
-          echo "🔐 Validating emergency token configuration..."
-          if [ -z "$CHARON_EMERGENCY_TOKEN" ]; then
-            echo "::error title=Missing Secret::CHARON_EMERGENCY_TOKEN secret not configured"
-            exit 1
-          fi
-          TOKEN_LENGTH=${#CHARON_EMERGENCY_TOKEN}
-          if [ $TOKEN_LENGTH -lt 64 ]; then
-            echo "::error title=Invalid Token Length::CHARON_EMERGENCY_TOKEN must be at least 64 characters"
-            exit 1
-          fi
-          MASKED_TOKEN="${CHARON_EMERGENCY_TOKEN:0:8}...${CHARON_EMERGENCY_TOKEN: -4}"
-          echo "::notice::Emergency token validated (length: $TOKEN_LENGTH, preview: $MASKED_TOKEN)"
-        env:
-          CHARON_EMERGENCY_TOKEN: ${{ secrets.CHARON_EMERGENCY_TOKEN }}
-
-      - name: Load Docker image
-        run: |
-          docker load -i charon-e2e-image.tar
-          docker images | grep charon
-
-      - name: Generate ephemeral encryption key
-        run: echo "CHARON_ENCRYPTION_KEY=$(openssl rand -base64 32)" >> $GITHUB_ENV
-
-      - name: Start test environment
-        run: |
-          docker compose -f .docker/compose/docker-compose.playwright-ci.yml --profile security-tests up -d
-          echo "✅ Container started for Chromium tests"
-
-      - name: Wait for service health
-        run: |
-          echo "⏳ Waiting for Charon to be healthy..."
-          MAX_ATTEMPTS=30
-          ATTEMPT=0
-          while [[ ${ATTEMPT} -lt ${MAX_ATTEMPTS} ]]; do
-            ATTEMPT=$((ATTEMPT + 1))
-            echo "Attempt ${ATTEMPT}/${MAX_ATTEMPTS}..."
-            if curl -sf http://127.0.0.1:8080/api/v1/health > /dev/null 2>&1; then
-              echo "✅ Charon is healthy!"
-              curl -s http://127.0.0.1:8080/api/v1/health | jq .
-              exit 0
-            fi
-            sleep 2
-          done
-          echo "❌ Health check failed"
-          docker compose -f .docker/compose/docker-compose.playwright-ci.yml logs
-          exit 1
-
-      - name: Install dependencies
-        run: npm ci
-
-      - name: Install Playwright Chromium
-        run: |
-          echo "📦 Installing Chromium..."
-          npx playwright install --with-deps chromium
-          EXIT_CODE=$?
-          echo "✅ Install command completed (exit code: $EXIT_CODE)"
-          echo "📁 Checking browser cache..."
-          ls -lR ~/.cache/ms-playwright/ 2>/dev/null || echo "Cache directory not found"
-          echo "🔍 Searching for chromium executable..."
-          find ~/.cache/ms-playwright -name "*chromium*" -o -name "*chrome*" 2>/dev/null | head -10 || echo "No chromium files found"
-          exit $EXIT_CODE
-
-      - name: Run Chromium tests (Shard ${{ matrix.shard }}/${{ matrix.total-shards }})
-        run: |
-          echo "════════════════════════════════════════════"
-          echo "Chromium E2E Tests - Shard ${{ matrix.shard }}/${{ matrix.total-shards }}"
-          echo "Start Time: $(date -u +'%Y-%m-%dT%H:%M:%SZ')"
-          echo "════════════════════════════════════════════"
-
-          SHARD_START=$(date +%s)
-          echo "SHARD_START=$SHARD_START" >> $GITHUB_ENV
-
-          npx playwright test \
-            --project=chromium \
-            --shard=${{ matrix.shard }}/${{ matrix.total-shards }}
-
-          SHARD_END=$(date +%s)
-          echo "SHARD_END=$SHARD_END" >> $GITHUB_ENV
-          SHARD_DURATION=$((SHARD_END - SHARD_START))
-          echo "════════════════════════════════════════════"
-          echo "Chromium Shard ${{ matrix.shard }} Complete | Duration: ${SHARD_DURATION}s"
-          echo "════════════════════════════════════════════"
-        env:
-          PLAYWRIGHT_BASE_URL: http://127.0.0.1:8080
-          CI: true
-          TEST_WORKER_INDEX: ${{ matrix.shard }}
-
-      - name: Upload HTML report (Chromium shard ${{ matrix.shard }})
-        if: always()
-        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6
-        with:
-          name: playwright-report-chromium-shard-${{ matrix.shard }}
-          path: playwright-report/
-          retention-days: 14
-
-      - name: Upload Chromium coverage (if enabled)
-        if: always() && env.PLAYWRIGHT_COVERAGE == '1'
-        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6
-        with:
-          name: e2e-coverage-chromium-shard-${{ matrix.shard }}
-          path: coverage/e2e/
-          retention-days: 7
-
-      - name: Upload test traces on failure
-        if: failure()
-        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6
-        with:
-          name: traces-chromium-shard-${{ matrix.shard }}
-          path: test-results/**/*.zip
-          retention-days: 7
-
-      - name: Collect Docker logs on failure
-        if: failure()
-        run: |
-          docker compose -f .docker/compose/docker-compose.playwright-ci.yml logs > docker-logs-chromium-shard-${{ matrix.shard }}.txt 2>&1
-
-      - name: Upload Docker logs on failure
-        if: failure()
-        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6
-        with:
-          name: docker-logs-chromium-shard-${{ matrix.shard }}
-          path: docker-logs-chromium-shard-${{ matrix.shard }}.txt
-          retention-days: 7
-
-      - name: Cleanup
-        if: always()
-        run: docker compose -f .docker/compose/docker-compose.playwright-ci.yml down -v 2>/dev/null || true
-
-  # Firefox browser tests (independent)
-  e2e-firefox:
-    name: E2E Firefox (Shard ${{ matrix.shard }}/${{ matrix.total-shards }})
-    runs-on: ubuntu-latest
-    needs: build
-    if: |
-      (github.event_name != 'workflow_dispatch') ||
-      (github.event.inputs.browser == 'firefox' || github.event.inputs.browser == 'all')
-    timeout-minutes: 45
-    env:
-      CHARON_EMERGENCY_TOKEN: ${{ secrets.CHARON_EMERGENCY_TOKEN }}
-      CHARON_EMERGENCY_SERVER_ENABLED: "true"
-      CHARON_SECURITY_TESTS_ENABLED: "true"
-      CHARON_E2E_IMAGE_TAG: charon:e2e-test
-    strategy:
-      fail-fast: false
-      matrix:
-        shard: [1]  # Single shard: all tests run sequentially to avoid race conditions
-        total-shards: [1]
-
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
-
-      - name: Set up Node.js
-        uses: actions/setup-node@6044e13b5dc448c55e2357c09f80417699197238 # v6
-        with:
-          node-version: ${{ env.NODE_VERSION }}
-          cache: 'npm'
-
-      - name: Download Docker image
-        uses: actions/download-artifact@37930b1c2abaa49bbe596cd826c3c89aef350131 # v7
-        with:
-          name: docker-image
-
-      - name: Validate Emergency Token Configuration
-        run: |
-          echo "🔐 Validating emergency token configuration..."
-          if [ -z "$CHARON_EMERGENCY_TOKEN" ]; then
-            echo "::error title=Missing Secret::CHARON_EMERGENCY_TOKEN secret not configured"
-            exit 1
-          fi
-          TOKEN_LENGTH=${#CHARON_EMERGENCY_TOKEN}
-          if [ $TOKEN_LENGTH -lt 64 ]; then
-            echo "::error title=Invalid Token Length::CHARON_EMERGENCY_TOKEN must be at least 64 characters"
-            exit 1
-          fi
-          MASKED_TOKEN="${CHARON_EMERGENCY_TOKEN:0:8}...${CHARON_EMERGENCY_TOKEN: -4}"
-          echo "::notice::Emergency token validated (length: $TOKEN_LENGTH, preview: $MASKED_TOKEN)"
-        env:
-          CHARON_EMERGENCY_TOKEN: ${{ secrets.CHARON_EMERGENCY_TOKEN }}
-
-      - name: Load Docker image
-        run: |
-          docker load -i charon-e2e-image.tar
-          docker images | grep charon
-
-      - name: Generate ephemeral encryption key
-        run: echo "CHARON_ENCRYPTION_KEY=$(openssl rand -base64 32)" >> $GITHUB_ENV
-
-      - name: Start test environment
-        run: |
-          docker compose -f .docker/compose/docker-compose.playwright-ci.yml --profile security-tests up -d
-          echo "✅ Container started for Firefox tests"
-
-      - name: Wait for service health
-        run: |
-          echo "⏳ Waiting for Charon to be healthy..."
-          MAX_ATTEMPTS=30
-          ATTEMPT=0
-          while [[ ${ATTEMPT} -lt ${MAX_ATTEMPTS} ]]; do
-            ATTEMPT=$((ATTEMPT + 1))
-            echo "Attempt ${ATTEMPT}/${MAX_ATTEMPTS}..."
-            if curl -sf http://127.0.0.1:8080/api/v1/health > /dev/null 2>&1; then
-              echo "✅ Charon is healthy!"
-              curl -s http://127.0.0.1:8080/api/v1/health | jq .
-              exit 0
-            fi
-            sleep 2
-          done
-          echo "❌ Health check failed"
-          docker compose -f .docker/compose/docker-compose.playwright-ci.yml logs
-          exit 1
-
-      - name: Install dependencies
-        run: npm ci
-
-      - name: Install Playwright Chromium
-        run: |
-          echo "📦 Installing Chromium (required by security-tests dependency)..."
-          npx playwright install --with-deps chromium
-          EXIT_CODE=$?
-          echo "✅ Install command completed (exit code: $EXIT_CODE)"
-          exit $EXIT_CODE
-
-      - name: Install Playwright Firefox
-        run: |
-          echo "📦 Installing Firefox..."
-          npx playwright install --with-deps firefox
-          EXIT_CODE=$?
-          echo "✅ Install command completed (exit code: $EXIT_CODE)"
-          echo "📁 Checking browser cache..."
-          ls -lR ~/.cache/ms-playwright/ 2>/dev/null || echo "Cache directory not found"
-          echo "🔍 Searching for firefox executable..."
-          find ~/.cache/ms-playwright -name "*firefox*" 2>/dev/null | head -10 || echo "No firefox files found"
-          exit $EXIT_CODE
-
-      - name: Run Firefox tests (Shard ${{ matrix.shard }}/${{ matrix.total-shards }})
-        run: |
-          echo "════════════════════════════════════════════"
-          echo "Firefox E2E Tests - Shard ${{ matrix.shard }}/${{ matrix.total-shards }}"
-          echo "Start Time: $(date -u +'%Y-%m-%dT%H:%M:%SZ')"
-          echo "════════════════════════════════════════════"
-
-          SHARD_START=$(date +%s)
-          echo "SHARD_START=$SHARD_START" >> $GITHUB_ENV
-
-          npx playwright test \
-            --project=firefox \
-            --shard=${{ matrix.shard }}/${{ matrix.total-shards }}
-
-          SHARD_END=$(date +%s)
-          echo "SHARD_END=$SHARD_END" >> $GITHUB_ENV
-          SHARD_DURATION=$((SHARD_END - SHARD_START))
-          echo "════════════════════════════════════════════"
-          echo "Firefox Shard ${{ matrix.shard }} Complete | Duration: ${SHARD_DURATION}s"
-          echo "════════════════════════════════════════════"
-        env:
-          PLAYWRIGHT_BASE_URL: http://127.0.0.1:8080
-          CI: true
-          TEST_WORKER_INDEX: ${{ matrix.shard }}
-
-      - name: Upload HTML report (Firefox shard ${{ matrix.shard }})
-        if: always()
-        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6
-        with:
-          name: playwright-report-firefox-shard-${{ matrix.shard }}
-          path: playwright-report/
-          retention-days: 14
-
-      - name: Upload Firefox coverage (if enabled)
-        if: always() && env.PLAYWRIGHT_COVERAGE == '1'
-        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6
-        with:
-          name: e2e-coverage-firefox-shard-${{ matrix.shard }}
-          path: coverage/e2e/
-          retention-days: 7
-
-      - name: Upload test traces on failure
-        if: failure()
-        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6
-        with:
-          name: traces-firefox-shard-${{ matrix.shard }}
-          path: test-results/**/*.zip
-          retention-days: 7
-
-      - name: Collect Docker logs on failure
-        if: failure()
-        run: |
-          docker compose -f .docker/compose/docker-compose.playwright-ci.yml logs > docker-logs-firefox-shard-${{ matrix.shard }}.txt 2>&1
-
-      - name: Upload Docker logs on failure
-        if: failure()
-        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6
-        with:
-          name: docker-logs-firefox-shard-${{ matrix.shard }}
-          path: docker-logs-firefox-shard-${{ matrix.shard }}.txt
-          retention-days: 7
-
-      - name: Cleanup
-        if: always()
-        run: docker compose -f .docker/compose/docker-compose.playwright-ci.yml down -v 2>/dev/null || true
-
-  # WebKit browser tests (independent)
-  e2e-webkit:
-    name: E2E WebKit (Shard ${{ matrix.shard }}/${{ matrix.total-shards }})
-    runs-on: ubuntu-latest
-    needs: build
-    if: |
-      (github.event_name != 'workflow_dispatch') ||
-      (github.event.inputs.browser == 'webkit' || github.event.inputs.browser == 'all')
-    timeout-minutes: 45
-    env:
-      CHARON_EMERGENCY_TOKEN: ${{ secrets.CHARON_EMERGENCY_TOKEN }}
-      CHARON_EMERGENCY_SERVER_ENABLED: "true"
-      CHARON_SECURITY_TESTS_ENABLED: "true"
-      CHARON_E2E_IMAGE_TAG: charon:e2e-test
-    strategy:
-      fail-fast: false
-      matrix:
-        shard: [1]  # Single shard: all tests run sequentially to avoid race conditions
-        total-shards: [1]
-
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
-
-      - name: Set up Node.js
-        uses: actions/setup-node@6044e13b5dc448c55e2357c09f80417699197238 # v6
-        with:
-          node-version: ${{ env.NODE_VERSION }}
-          cache: 'npm'
-
-      - name: Download Docker image
-        uses: actions/download-artifact@37930b1c2abaa49bbe596cd826c3c89aef350131 # v7
-        with:
-          name: docker-image
-
-      - name: Validate Emergency Token Configuration
-        run: |
-          echo "🔐 Validating emergency token configuration..."
-          if [ -z "$CHARON_EMERGENCY_TOKEN" ]; then
-            echo "::error title=Missing Secret::CHARON_EMERGENCY_TOKEN secret not configured"
-            exit 1
-          fi
-          TOKEN_LENGTH=${#CHARON_EMERGENCY_TOKEN}
-          if [ $TOKEN_LENGTH -lt 64 ]; then
-            echo "::error title=Invalid Token Length::CHARON_EMERGENCY_TOKEN must be at least 64 characters"
-            exit 1
-          fi
-          MASKED_TOKEN="${CHARON_EMERGENCY_TOKEN:0:8}...${CHARON_EMERGENCY_TOKEN: -4}"
-          echo "::notice::Emergency token validated (length: $TOKEN_LENGTH, preview: $MASKED_TOKEN)"
-        env:
-          CHARON_EMERGENCY_TOKEN: ${{ secrets.CHARON_EMERGENCY_TOKEN }}
-
-      - name: Load Docker image
-        run: |
-          docker load -i charon-e2e-image.tar
-          docker images | grep charon
-
-      - name: Generate ephemeral encryption key
-        run: echo "CHARON_ENCRYPTION_KEY=$(openssl rand -base64 32)" >> $GITHUB_ENV
-
-      - name: Start test environment
-        run: |
-          docker compose -f .docker/compose/docker-compose.playwright-ci.yml --profile security-tests up -d
-          echo "✅ Container started for WebKit tests"
-
-      - name: Wait for service health
-        run: |
-          echo "⏳ Waiting for Charon to be healthy..."
-          MAX_ATTEMPTS=30
-          ATTEMPT=0
-          while [[ ${ATTEMPT} -lt ${MAX_ATTEMPTS} ]]; do
-            ATTEMPT=$((ATTEMPT + 1))
-            echo "Attempt ${ATTEMPT}/${MAX_ATTEMPTS}..."
-            if curl -sf http://127.0.0.1:8080/api/v1/health > /dev/null 2>&1; then
-              echo "✅ Charon is healthy!"
-              curl -s http://127.0.0.1:8080/api/v1/health | jq .
-              exit 0
-            fi
-            sleep 2
-          done
-          echo "❌ Health check failed"
-          docker compose -f .docker/compose/docker-compose.playwright-ci.yml logs
-          exit 1
-
-      - name: Install dependencies
-        run: npm ci
-
-      - name: Install Playwright Chromium
-        run: |
-          echo "📦 Installing Chromium (required by security-tests dependency)..."
-          npx playwright install --with-deps chromium
-          EXIT_CODE=$?
-          echo "✅ Install command completed (exit code: $EXIT_CODE)"
-          exit $EXIT_CODE
-
-      - name: Install Playwright WebKit
-        run: |
-          echo "📦 Installing WebKit..."
-          npx playwright install --with-deps webkit
-          EXIT_CODE=$?
-          echo "✅ Install command completed (exit code: $EXIT_CODE)"
-          echo "📁 Checking browser cache..."
-          ls -lR ~/.cache/ms-playwright/ 2>/dev/null || echo "Cache directory not found"
-          echo "🔍 Searching for webkit executable..."
-          find ~/.cache/ms-playwright -name "*webkit*" -o -name "*MiniBrowser*" 2>/dev/null | head -10 || echo "No webkit files found"
-          exit $EXIT_CODE
-
-      - name: Run WebKit tests (Shard ${{ matrix.shard }}/${{ matrix.total-shards }})
-        run: |
-          echo "════════════════════════════════════════════"
-          echo "WebKit E2E Tests - Shard ${{ matrix.shard }}/${{ matrix.total-shards }}"
-          echo "Start Time: $(date -u +'%Y-%m-%dT%H:%M:%SZ')"
-          echo "════════════════════════════════════════════"
-
-          SHARD_START=$(date +%s)
-          echo "SHARD_START=$SHARD_START" >> $GITHUB_ENV
-
-          npx playwright test \
-            --project=webkit \
-            --shard=${{ matrix.shard }}/${{ matrix.total-shards }}
-
-          SHARD_END=$(date +%s)
-          echo "SHARD_END=$SHARD_END" >> $GITHUB_ENV
-          SHARD_DURATION=$((SHARD_END - SHARD_START))
-          echo "════════════════════════════════════════════"
-          echo "WebKit Shard ${{ matrix.shard }} Complete | Duration: ${SHARD_DURATION}s"
-          echo "════════════════════════════════════════════"
-        env:
-          PLAYWRIGHT_BASE_URL: http://127.0.0.1:8080
-          CI: true
-          TEST_WORKER_INDEX: ${{ matrix.shard }}
-
-      - name: Upload HTML report (WebKit shard ${{ matrix.shard }})
-        if: always()
-        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6
-        with:
-          name: playwright-report-webkit-shard-${{ matrix.shard }}
-          path: playwright-report/
-          retention-days: 14
-
-      - name: Upload WebKit coverage (if enabled)
-        if: always() && env.PLAYWRIGHT_COVERAGE == '1'
-        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6
-        with:
-          name: e2e-coverage-webkit-shard-${{ matrix.shard }}
-          path: coverage/e2e/
-          retention-days: 7
-
-      - name: Upload test traces on failure
-        if: failure()
-        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6
-        with:
-          name: traces-webkit-shard-${{ matrix.shard }}
-          path: test-results/**/*.zip
-          retention-days: 7
-
-      - name: Collect Docker logs on failure
-        if: failure()
-        run: |
-          docker compose -f .docker/compose/docker-compose.playwright-ci.yml logs > docker-logs-webkit-shard-${{ matrix.shard }}.txt 2>&1
-
-      - name: Upload Docker logs on failure
-        if: failure()
-        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6
-        with:
-          name: docker-logs-webkit-shard-${{ matrix.shard }}
-          path: docker-logs-webkit-shard-${{ matrix.shard }}.txt
-          retention-days: 7
-
-      - name: Cleanup
-        if: always()
-        run: docker compose -f .docker/compose/docker-compose.playwright-ci.yml down -v 2>/dev/null || true
-
-  # Test summary job
-  test-summary:
-    name: E2E Test Summary
-    runs-on: ubuntu-latest
-    needs: [e2e-chromium, e2e-firefox, e2e-webkit]
-    if: always()
-
-    steps:
-      - name: Generate job summary
-        run: |
-          echo "## 📊 E2E Test Results (Split Browser Jobs)" >> $GITHUB_STEP_SUMMARY
-          echo "" >> $GITHUB_STEP_SUMMARY
-          echo "### Browser Job Status" >> $GITHUB_STEP_SUMMARY
-          echo "" >> $GITHUB_STEP_SUMMARY
-          echo "| Browser | Status | Shards | Notes |" >> $GITHUB_STEP_SUMMARY
-          echo "|---------|--------|--------|-------|" >> $GITHUB_STEP_SUMMARY
-          echo "| Chromium | ${{ needs.e2e-chromium.result }} | 1 | Sequential execution |" >> $GITHUB_STEP_SUMMARY
-          echo "| Firefox | ${{ needs.e2e-firefox.result }} | 1 | Sequential execution |" >> $GITHUB_STEP_SUMMARY
-          echo "| WebKit | ${{ needs.e2e-webkit.result }} | 1 | Sequential execution |" >> $GITHUB_STEP_SUMMARY
-          echo "" >> $GITHUB_STEP_SUMMARY
-          echo "### Phase 1 Hotfix Benefits" >> $GITHUB_STEP_SUMMARY
-          echo "" >> $GITHUB_STEP_SUMMARY
-          echo "- ✅ **Browser Parallelism:** All 3 browsers run simultaneously (job-level)" >> $GITHUB_STEP_SUMMARY
-          echo "- ℹ️  **Sequential Tests:** Each browser runs all tests sequentially (no sharding)" >> $GITHUB_STEP_SUMMARY
-          echo "" >> $GITHUB_STEP_SUMMARY
-          echo "### Per-Shard HTML Reports" >> $GITHUB_STEP_SUMMARY
-          echo "" >> $GITHUB_STEP_SUMMARY
-          echo "Download artifacts to view detailed test results for each browser and shard." >> $GITHUB_STEP_SUMMARY
-
-  # Upload merged coverage to Codecov with browser-specific flags
-  upload-coverage:
-    name: Upload E2E Coverage
-    runs-on: ubuntu-latest
-    needs: [e2e-chromium, e2e-firefox, e2e-webkit]
-    if: vars.PLAYWRIGHT_COVERAGE == '1' && always()
-
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
-
-      - name: Download all coverage artifacts
-        uses: actions/download-artifact@37930b1c2abaa49bbe596cd826c3c89aef350131 # v7
-        with:
-          pattern: e2e-coverage-*
-          path: all-coverage
-          merge-multiple: false
-
-      - name: Merge browser coverage files
-        run: |
-          sudo apt-get update && sudo apt-get install -y lcov
-          mkdir -p coverage/e2e-merged/{chromium,firefox,webkit}
-
-          # Merge Chromium shards
-          CHROMIUM_FILES=$(find all-coverage -path "*chromium*" -name "lcov.info" -type f)
-          if [[ -n "$CHROMIUM_FILES" ]]; then
-            MERGE_ARGS=""
-            for file in $CHROMIUM_FILES; do MERGE_ARGS="$MERGE_ARGS -a $file"; done
-            lcov $MERGE_ARGS -o coverage/e2e-merged/chromium/lcov.info
-            echo "✅ Merged $(echo "$CHROMIUM_FILES" | wc -w) Chromium coverage files"
-          fi
-
-          # Merge Firefox shards
-          FIREFOX_FILES=$(find all-coverage -path "*firefox*" -name "lcov.info" -type f)
-          if [[ -n "$FIREFOX_FILES" ]]; then
-            MERGE_ARGS=""
-            for file in $FIREFOX_FILES; do MERGE_ARGS="$MERGE_ARGS -a $file"; done
-            lcov $MERGE_ARGS -o coverage/e2e-merged/firefox/lcov.info
-            echo "✅ Merged $(echo "$FIREFOX_FILES" | wc -w) Firefox coverage files"
-          fi
-
-          # Merge WebKit shards
-          WEBKIT_FILES=$(find all-coverage -path "*webkit*" -name "lcov.info" -type f)
-          if [[ -n "$WEBKIT_FILES" ]]; then
-            MERGE_ARGS=""
-            for file in $WEBKIT_FILES; do MERGE_ARGS="$MERGE_ARGS -a $file"; done
-            lcov $MERGE_ARGS -o coverage/e2e-merged/webkit/lcov.info
-            echo "✅ Merged $(echo "$WEBKIT_FILES" | wc -w) WebKit coverage files"
-          fi
-
-      - name: Upload Chromium coverage to Codecov
-        if: hashFiles('coverage/e2e-merged/chromium/lcov.info') != ''
-        uses: codecov/codecov-action@671740ac38dd9b0130fbe1cec585b89eea48d3de # v5
-        with:
-          token: ${{ secrets.CODECOV_TOKEN }}
-          files: ./coverage/e2e-merged/chromium/lcov.info
-          flags: e2e-chromium
-          name: e2e-coverage-chromium
-          fail_ci_if_error: false
-
-      - name: Upload Firefox coverage to Codecov
-        if: hashFiles('coverage/e2e-merged/firefox/lcov.info') != ''
-        uses: codecov/codecov-action@671740ac38dd9b0130fbe1cec585b89eea48d3de # v5
-        with:
-          token: ${{ secrets.CODECOV_TOKEN }}
-          files: ./coverage/e2e-merged/firefox/lcov.info
-          flags: e2e-firefox
-          name: e2e-coverage-firefox
-          fail_ci_if_error: false
-
-      - name: Upload WebKit coverage to Codecov
-        if: hashFiles('coverage/e2e-merged/webkit/lcov.info') != ''
-        uses: codecov/codecov-action@671740ac38dd9b0130fbe1cec585b89eea48d3de # v5
-        with:
-          token: ${{ secrets.CODECOV_TOKEN }}
-          files: ./coverage/e2e-merged/webkit/lcov.info
-          flags: e2e-webkit
-          name: e2e-coverage-webkit
-          fail_ci_if_error: false
-
-      - name: Upload merged coverage artifacts
-        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6
-        with:
-          name: e2e-coverage-merged
-          path: coverage/e2e-merged/
-          retention-days: 30
-
-  # Comment on PR with results
-  comment-results:
-    name: Comment Test Results
-    runs-on: ubuntu-latest
-    needs: [e2e-chromium, e2e-firefox, e2e-webkit, test-summary]
-    if: github.event_name == 'pull_request' && always()
-    permissions:
-      pull-requests: write
-
-    steps:
-      - name: Determine overall status
-        id: status
-        run: |
-          CHROMIUM="${{ needs.e2e-chromium.result }}"
-          FIREFOX="${{ needs.e2e-firefox.result }}"
-          WEBKIT="${{ needs.e2e-webkit.result }}"
-
-          if [[ "$CHROMIUM" == "success" && "$FIREFOX" == "success" && "$WEBKIT" == "success" ]]; then
-            echo "emoji=✅" >> $GITHUB_OUTPUT
-            echo "status=PASSED" >> $GITHUB_OUTPUT
-            echo "message=All browser tests passed!" >> $GITHUB_OUTPUT
-          else
-            echo "emoji=❌" >> $GITHUB_OUTPUT
-            echo "status=FAILED" >> $GITHUB_OUTPUT
-            echo "message=Some browser tests failed. Each browser runs independently." >> $GITHUB_OUTPUT
-          fi
-
-      - name: Comment on PR
-        uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8
-        with:
-          script: |
-            const emoji = '${{ steps.status.outputs.emoji }}';
-            const status = '${{ steps.status.outputs.status }}';
-            const message = '${{ steps.status.outputs.message }}';
-            const chromium = '${{ needs.e2e-chromium.result }}';
-            const firefox = '${{ needs.e2e-firefox.result }}';
-            const webkit = '${{ needs.e2e-webkit.result }}';
-            const runUrl = `https://github.com/${context.repo.owner}/${context.repo.repo}/actions/runs/${context.runId}`;
-
-            const body = `## ${emoji} E2E Test Results: ${status} (Split Browser Jobs)
-
-            ${message}
-
-            ### Browser Results (Sequential Execution)
-            | Browser | Status | Shards | Execution |
-            |---------|--------|--------|-----------|
-            | Chromium | ${chromium === 'success' ? '✅ Passed' : chromium === 'failure' ? '❌ Failed' : '⚠️ ' + chromium} | 1 | Sequential |
-            | Firefox | ${firefox === 'success' ? '✅ Passed' : firefox === 'failure' ? '❌ Failed' : '⚠️ ' + firefox} | 1 | Sequential |
-            | WebKit | ${webkit === 'success' ? '✅ Passed' : webkit === 'failure' ? '❌ Failed' : '⚠️ ' + webkit} | 1 | Sequential |
-
-            **Phase 1 Hotfix Active:** Each browser runs in a separate job. One browser failure does not block others.
-
-            [📊 View workflow run & download reports](${runUrl})
-
-            ---
-            <sub>🤖 Phase 1 Emergency Hotfix - See docs/plans/browser_alignment_triage.md</sub>`;
-
-            const { data: comments } = await github.rest.issues.listComments({
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              issue_number: context.issue.number,
-            });
-
-            const botComment = comments.find(comment =>
-              comment.user.type === 'Bot' &&
-              comment.body.includes('E2E Test Results')
-            );
-
-            if (botComment) {
-              await github.rest.issues.updateComment({
-                owner: context.repo.owner,
-                repo: context.repo.repo,
-                comment_id: botComment.id,
-                body: body
-              });
-            } else {
-              await github.rest.issues.createComment({
-                owner: context.repo.owner,
-                repo: context.repo.repo,
-                issue_number: context.issue.number,
-                body: body
-              });
-            }
-
-  # Final status check
-  e2e-results:
-    name: E2E Test Results (Final)
-    runs-on: ubuntu-latest
-    needs: [e2e-chromium, e2e-firefox, e2e-webkit]
-    if: always()
-
-    steps:
-      - name: Check test results
-        run: |
-          CHROMIUM="${{ needs.e2e-chromium.result }}"
-          FIREFOX="${{ needs.e2e-firefox.result }}"
-          WEBKIT="${{ needs.e2e-webkit.result }}"
-
-          echo "Browser Results:"
-          echo "  Chromium: $CHROMIUM"
-          echo "  Firefox: $FIREFOX"
-          echo "  WebKit: $WEBKIT"
-
-          # Allow skipped browsers (workflow_dispatch with specific browser)
-          if [[ "$CHROMIUM" == "skipped" ]]; then CHROMIUM="success"; fi
-          if [[ "$FIREFOX" == "skipped" ]]; then FIREFOX="success"; fi
-          if [[ "$WEBKIT" == "skipped" ]]; then WEBKIT="success"; fi
-
-          if [[ "$CHROMIUM" == "success" && "$FIREFOX" == "success" && "$WEBKIT" == "success" ]]; then
-            echo "✅ All browser tests passed or were skipped"
-            exit 0
-          else
-            echo "❌ One or more browser tests failed"
-            exit 1
-          fi

.github/workflows/propagate-changes.yml

@@ -5,6 +5,7 @@ on:
     branches:
       - main
       - development
+      - 'feature/**'
       - 'hotfix/**'
 
 concurrency:
@@ -35,6 +36,25 @@ jobs:
         with:
           script: |
             const currentBranch = context.ref.replace('refs/heads/', '');
+            let excludedBranch = null;
+
+            // Loop Prevention: Identify if this commit is from a merged PR
+            try {
+              const associatedPRs = await github.rest.repos.listPullRequestsAssociatedWithCommit({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                commit_sha: context.sha,
+              });
+
+              // If the commit comes from a PR, we identify the source branch
+              // so we don't try to merge changes back into it immediately.
+              if (associatedPRs.data.length > 0) {
+                excludedBranch = associatedPRs.data[0].head.ref;
+                core.info(`Commit ${context.sha} is associated with PR #${associatedPRs.data[0].number} coming from '${excludedBranch}'. This branch will be excluded from propagation to prevent loops.`);
+              }
+            } catch (err) {
+              core.warning(`Failed to check associated PRs: ${err.message}`);
+            }
 
             async function createPR(src, base) {
               if (src === base) return;
@@ -148,22 +168,35 @@ jobs:
 
             if (currentBranch === 'main') {
               // Main -> Development
-              await createPR('main', 'development');
+              // Only propagate if development is not the source (loop prevention)
+              if (excludedBranch !== 'development') {
+                await createPR('main', 'development');
+              } else {
+                core.info('Push originated from development (excluded). Skipping propagation back to development.');
+              }
             } else if (currentBranch === 'development') {
-              // Development -> Feature branches (direct, no nightly intermediary)
+              // Development -> Feature/Hotfix branches (The Pittsburgh Model)
+              // We propagate changes from dev DOWN to features/hotfixes so they stay up to date.
+
               const branches = await github.paginate(github.rest.repos.listBranches, {
                 owner: context.repo.owner,
                 repo: context.repo.repo,
               });
 
-              const featureBranches = branches
+              // Filter for feature/* and hotfix/* branches using regex
+              // AND exclude the branch that just got merged in (if any)
+              const targetBranches = branches
                 .map(b => b.name)
-                .filter(name => name.startsWith('feature/'));
+                .filter(name => {
+                  const isTargetType = /^feature\/|^hotfix\//.test(name);
+                  const isExcluded = (name === excludedBranch);
+                  return isTargetType && !isExcluded;
+                });
 
-              core.info(`Found ${featureBranches.length} feature branches: ${featureBranches.join(', ')}`);
+              core.info(`Found ${targetBranches.length} target branches (excluding '${excludedBranch || 'none'}'): ${targetBranches.join(', ')}`);
 
-              for (const featureBranch of featureBranches) {
-                await createPR('development', featureBranch);
+              for (const targetBranch of targetBranches) {
+                await createPR('development', targetBranch);
               }
             }
         env: