chore: clean .gitignore cache

.github/workflows/benchmark.yml

@@ -0,0 +1,81 @@
+name: Go Benchmark
+
+on:
+  push:
+    branches:
+      - main
+      - development
+    paths:
+      - 'backend/**'
+  pull_request:
+    branches:
+      - main
+      - development
+    paths:
+      - 'backend/**'
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+env:
+  GO_VERSION: '1.25.6'
+  GOTOOLCHAIN: auto
+
+# Minimal permissions at workflow level; write permissions granted at job level for push only
+permissions:
+  contents: read
+
+jobs:
+  benchmark:
+    name: Performance Regression Check
+    runs-on: ubuntu-latest
+    # Grant write permissions for storing benchmark results (only used on push via step condition)
+    # Note: GitHub Actions doesn't support dynamic expressions in permissions block
+    permissions:
+      contents: write
+      deployments: write
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6
+
+      - name: Set up Go
+        uses: actions/setup-go@7a3fe6cf4cb3a834922a1244abfce67bcef6a0c5 # v6
+        with:
+          go-version: ${{ env.GO_VERSION }}
+          cache-dependency-path: backend/go.sum
+
+      - name: Run Benchmark
+        working-directory: backend
+        run: go test -bench=. -benchmem -run='^$' ./... | tee output.txt
+
+      - name: Store Benchmark Result
+        # Only store results on pushes to main - PRs just run benchmarks without storage
+        # This avoids gh-pages branch errors and permission issues on fork PRs
+        if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+        # Security: Pinned to full SHA for supply chain security
+        uses: benchmark-action/github-action-benchmark@4e0b38bc48375986542b13c0d8976b7b80c60c00 # v1
+        with:
+          name: Go Benchmark
+          tool: 'go'
+          output-file-path: backend/output.txt
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          auto-push: true
+          # Show alert with commit comment on detection of performance regression
+          # Threshold increased to 175% to account for CI variability
+          alert-threshold: '175%'
+          comment-on-alert: true
+          fail-on-alert: false
+          # Enable Job Summary
+          summary-always: true
+
+      - name: Run Perf Asserts
+        working-directory: backend
+        env:
+          PERF_MAX_MS_GETSTATUS_P95: 500ms
+          PERF_MAX_MS_GETSTATUS_P95_PARALLEL: 1500ms
+          PERF_MAX_MS_LISTDECISIONS_P95: 2000ms
+        run: |
+          echo "## 🔍 Running performance assertions (TestPerf)" >> $GITHUB_STEP_SUMMARY
+          go test -run TestPerf -v ./internal/api/handlers -count=1 | tee perf-output.txt
+          exit ${PIPESTATUS[0]}