chore: drop frontend CI jobs until #21 lands the scaffold

.github/workflows/ci.yml

@@ -95,34 +95,7 @@ jobs:
       - run: uv sync --frozen --extra dev
       - run: uv run pre-commit run --all-files --show-diff-on-failure
 
-  frontend-build:
-    name: Frontend Build
-    runs-on: ubuntu-latest
-    # Skips cleanly until ticket #21 lands frontend/package.json.
-    if: hashFiles('frontend/package.json') != ''
-    steps:
-      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5  # v4
-      - uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e  # v6
-        with:
-          node-version: "24"
-          cache: npm
-          cache-dependency-path: frontend/package-lock.json
-      - run: cd frontend && npm ci && npm run build
-
-  frontend-quality:
-    name: Frontend Quality
-    runs-on: ubuntu-latest
-    # Lint + format + tsc + vitest.
-    if: hashFiles('frontend/package.json') != ''
-    steps:
-      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5  # v4
-      - uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e  # v6
-        with:
-          node-version: "24"
-          cache: npm
-          cache-dependency-path: frontend/package-lock.json
-      - run: cd frontend && npm ci
-      - run: cd frontend && npm run lint
-      - run: cd frontend && npm run format:check
-      - run: cd frontend && npm run check
-      - run: cd frontend && npm run test
+  # Frontend jobs (Frontend Build, Frontend Quality) are added by ticket #21
+  # when frontend/package.json lands; keeping them out of this file avoids the
+  # workflow-startup failure observed when `if: hashFiles(...)` guards a job
+  # whose `cache-dependency-path` references a not-yet-existing file.