ci: run the frontend tests with coverage, enforcing the 90% thresholds

The bar codified in WP-14 is cleared as of 2.2.1, so the job that was
deliberately left as a plain run - "gating CI on a bar the codebase is
known not to clear would be a permanently red job nobody reads" - now
enforces it.

.gitea/workflows/ci.yml

@@ -40,12 +40,11 @@ jobs:
           cache: npm
           cache-dependency-path: package-lock.json
       - run: npm ci
-      # Plain run, not coverage. The coverage thresholds in vite.config.ts are
-      # the policy (90/85) and `npm run test:cov` enforces them locally; the
-      # suite does not meet them yet, and gating CI on a bar the codebase is
-      # known not to clear would just be a permanently red job nobody reads.
-      # Switch this to `npm run test:cov` once WP-14's coverage work lands.
-      - run: npm test
+      # With coverage: vite.config.ts codifies the 90% thresholds and this is
+      # what enforces them. The suite cleared the bar in WP-19 (from 14%), so
+      # a change that drops below it now fails the job rather than a number
+      # in a report nobody reads.
+      - run: npm run test:cov
 
   secrets-scan:
     runs-on: ubuntu-latest