Make frontend coverage download conditional

Add inputs to the coverage-aggregate workflow to control downloading frontend coverage artifacts (download_vitest_coverage, download_playwright_coverage) and default them to true. Update build.yml to pass those flags based on frontend-validation and playwright-e2e-live job results. Guard artifact download steps with the new inputs and standardize the Playwright artifact name to a stable value (playwright-frontend-coverage). Continue-on-error behavior retained so backend-only PRs remain resilient.

.github/workflows/build.yml

@@ -201,6 +201,9 @@ jobs:
     permissions:
       contents: read
     uses: ./.github/workflows/coverage-aggregate.yml
+    with:
+      download_vitest_coverage: ${{ needs.frontend-validation.result == 'success' }}
+      download_playwright_coverage: ${{ needs.playwright-e2e-live.result == 'success' }}
     secrets: inherit
 
   # Single status check that branch protection should mark as required.

.github/workflows/coverage-aggregate.yml

@@ -13,6 +13,17 @@ name: Aggregate backend coverage
 #     producers themselves
 on:
   workflow_call:
+    inputs:
+      download_vitest_coverage:
+        description: Download the frontend-validation coverage artifact when available.
+        required: false
+        type: boolean
+        default: true
+      download_playwright_coverage:
+        description: Download the e2e-live Playwright coverage artifact when available.
+        required: false
+        type: boolean
+        default: true
 
 permissions:
   contents: read
@@ -198,7 +209,7 @@ jobs:
         # frontend-validation uploads as `frontend-coverage`. Tolerate
         # absence so a backend-only PR still produces the matrix with
         # just backend rows populated.
-        if: always()
+        if: always() && inputs.download_vitest_coverage
         uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v6.0.0
         with:
           name: frontend-coverage
@@ -206,12 +217,12 @@ jobs:
         continue-on-error: true
 
       - name: Download Playwright frontend coverage artifact
-        # e2e-live uploads as `playwright-frontend-coverage-<run_id>`.
+        # e2e-live uploads the artifact with a stable name.
         # Same tolerance as vitest - matrix script handles missing inputs.
-        if: always()
+        if: always() && inputs.download_playwright_coverage
         uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v6.0.0
         with:
-          name: playwright-frontend-coverage-${{ github.run_id }}
+          name: playwright-frontend-coverage
           path: matrix-inputs/playwright/
         continue-on-error: true
 

.github/workflows/e2e-live.yml

@@ -169,7 +169,7 @@ jobs:
         if: always() && steps.pw-frontend-coverage.outputs.summary == 'true'
         uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with:
-          name: playwright-frontend-coverage-${{ github.run_id }}
+          name: playwright-frontend-coverage
           path: |
             .test-state/playwright/coverage-pw-summary/
             .test-state/playwright/coverage-pw/