chore(ci): enable scheduled container pruning and report reclaimed space

- Make container prune run perform deletions by default (workflow_dispatch default now false for dry_run)
- Enhance prune script to estimate candidate and deleted image sizes (Docker Hub best-effort; GHCR manifest fallback)
- Emit machine-readable summary (`prune-summary.env`) and human-readable summary to the workflow run
- Upload logs + summary as artifacts and expose `space_saved` in the run summary

Why:
- Previously the scheduled job used dry-run by default and only logged candidates; this change makes scheduled pruning effective and provides visibility into storage reclaimed.

Impact:
- Runs will now remove eligible images by default (use dry_run=true to test)
- Size calculations are best-effort and may be incomplete if registry APIs do not expose sizes

.github/workflows/container-prune.yml

@@ -35,7 +35,7 @@ jobs:
       REGISTRIES: ${{ github.event.inputs.registries || 'ghcr,dockerhub' }}
       KEEP_DAYS: ${{ github.event.inputs.keep_days || '30' }}
       KEEP_LAST_N: ${{ github.event.inputs.keep_last_n || '30' }}
-      DRY_RUN: ${{ github.event.inputs.dry_run || 'true' }}
+      DRY_RUN: ${{ github.event.inputs.dry_run || 'false' }}
       PROTECTED_REGEX: '["^v","^latest$","^main$","^develop$"]'
     steps:
       - name: Checkout
@@ -45,7 +45,7 @@ jobs:
         run: |
           sudo apt-get update && sudo apt-get install -y jq curl
 
-      - name: Run container prune (dry-run by default)
+      - name: Run container prune
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           DOCKERHUB_USERNAME: ${{ secrets.DOCKERHUB_USERNAME }}
@@ -54,10 +54,57 @@ jobs:
           chmod +x scripts/prune-container-images.sh
           ./scripts/prune-container-images.sh 2>&1 | tee prune-${{ github.run_id }}.log
 
-      - name: Upload log
+      - name: Summarize prune results (space reclaimed)
+        if: ${{ always() }}
+        run: |
+          set -euo pipefail
+          SUMMARY_FILE=prune-summary.env
+          LOG_FILE=prune-${{ github.run_id }}.log
+
+          human() {
+            local bytes=${1:-0}
+            if [ -z "$bytes" ] || [ "$bytes" -eq 0 ]; then
+              echo "0 B"
+              return
+            fi
+            awk -v b="$bytes" 'function human(x){ split("B KiB MiB GiB TiB",u," "); i=0; while(x>1024){x/=1024;i++} printf "%0.2f %s", x, u[i+1]} END{human(b)}'
+          }
+
+          if [ -f "$SUMMARY_FILE" ]; then
+            TOTAL_CANDIDATES=$(grep -E '^TOTAL_CANDIDATES=' "$SUMMARY_FILE" | cut -d= -f2 || echo 0)
+            TOTAL_CANDIDATES_BYTES=$(grep -E '^TOTAL_CANDIDATES_BYTES=' "$SUMMARY_FILE" | cut -d= -f2 || echo 0)
+            TOTAL_DELETED=$(grep -E '^TOTAL_DELETED=' "$SUMMARY_FILE" | cut -d= -f2 || echo 0)
+            TOTAL_DELETED_BYTES=$(grep -E '^TOTAL_DELETED_BYTES=' "$SUMMARY_FILE" | cut -d= -f2 || echo 0)
+
+            {
+              echo "## Container prune summary"
+              echo "- candidates: ${TOTAL_CANDIDATES} (≈ $(human "${TOTAL_CANDIDATES_BYTES}"))"
+              echo "- deleted: ${TOTAL_DELETED} (≈ $(human "${TOTAL_DELETED_BYTES}"))"
+            } >> "$GITHUB_STEP_SUMMARY"
+
+            printf 'PRUNE_SUMMARY: candidates=%s candidates_bytes=%s deleted=%s deleted_bytes=%s\n' \
+              "${TOTAL_CANDIDATES}" "${TOTAL_CANDIDATES_BYTES}" "${TOTAL_DELETED}" "${TOTAL_DELETED_BYTES}"
+            echo "Deleted approximately: $(human "${TOTAL_DELETED_BYTES}")"
+            echo "space_saved=$(human "${TOTAL_DELETED_BYTES}")" >> "$GITHUB_OUTPUT"
+          else
+            deleted_bytes=$(grep -oE '\( *approx +[0-9]+ bytes\)' "$LOG_FILE" | sed -E 's/.*approx +([0-9]+) bytes.*/\1/' | awk '{s+=$1} END {print s+0}' || true)
+            deleted_count=$(grep -cE 'deleting |DRY RUN: would delete' "$LOG_FILE" || true)
+
+            {
+              echo "## Container prune summary"
+              echo "- deleted (approx): ${deleted_count} (≈ $(human "${deleted_bytes}"))"
+            } >> "$GITHUB_STEP_SUMMARY"
+
+            printf 'PRUNE_SUMMARY: deleted_approx=%s deleted_bytes=%s\n' "${deleted_count}" "${deleted_bytes}"
+            echo "Deleted approximately: $(human "${deleted_bytes}")"
+            echo "space_saved=$(human "${deleted_bytes}")" >> "$GITHUB_OUTPUT"
+          fi
+
+      - name: Upload prune artifacts
         if: ${{ always() }}
         uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6
         with:
           name: prune-log-${{ github.run_id }}
           path: |
             prune-${{ github.run_id }}.log
+            prune-summary.env