ci: gate the .env.example template in CI (E00-S04-T05)

.gitea/workflows/ci.yml

@@ -287,6 +287,27 @@ jobs:
       - name: Run config schema test suite
         run: node --test tests/config-schema.test.mjs
 
+  # E00-S04-T05: the static assertions of tests/env-example.test.mjs gate every
+  # PR — the suite locks in the committed `.env.example` template: it exists at
+  # the repo root, is un-ignored in .gitignore (real `.env` files stay ignored
+  # while the example is tracked), documents every configuration environment
+  # source (HOST/PORT/DATABASE_URL/EPPP_SESSION_SECRET), and contains
+  # placeholder values only — no credential URI, no long secret-looking value,
+  # and no compose default credential — with mutation probes proving the
+  # assertions are non-vacuous. The test needs no dependencies, so the job
+  # only installs Node.
+  env-example:
+    name: .env.example placeholders only (E00-S04-T05)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Node.js 24
+        uses: actions/setup-node@v4
+        with:
+          node-version: '24'
+      - name: Run .env.example test suite
+        run: node --test tests/env-example.test.mjs
+
   # E00-S03-T01: the static assertions of tests/compose-config.test.mjs (db
   # image pinned to postgres:18.6-bookworm, health gate, volume persistence,
   # build platforms) gate every PR (the docker-gated real-stack probes inside