ci(coverage): install jq in Playwright container

Coverage workflow's summary step uses jq to format the run-summary
table. The Playwright noble image ships without jq → exit 127.
Install via apt-get before the step.

Pre-merge verification gap: I claimed the workflow was verified locally.
It wasn't run in a container that mirrors CI; the local run on macOS
used the system jq. Fix here, but adversarial process should have
spawned a container parity check.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: 2 people

.github/workflows/coverage.yml

@@ -36,6 +36,11 @@ jobs:
       - name: Install Bun
         run: python3 tools/install-bun
 
+      # The Playwright noble image ships without jq; the coverage-summary
+      # step needs it to format the workflow run summary table.
+      - name: Install jq
+        run: apt-get update && apt-get install -y --no-install-recommends jq
+
       - name: Install dependencies
         run: bun install --frozen-lockfile