ci: run the sync round-trip against a real Postgres, and document it

CI starts postgres:16-alpine and the sync server before npm test, so the
round-trip runs for real instead of skipping. A fake would not exercise
the change_seq trigger, the last-write-wins upsert or cursor paging, which
is exactly where sync goes wrong.

Also corrects the stale advisory count in the validate.mjs comment: the
updated export bundle carries data/gloss-extra.json, and the baseline has
been 0 blocking, 0 advisory since it landed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.github/workflows/ci.yml

@@ -14,7 +14,7 @@ jobs:
 
       # The curriculum gate comes first, before anything else can run.
       # validate.mjs reads only data/ and lib/ and exits non-zero on a
-      # blocking failure. Baseline: PASS — 0 blocking, 167 advisory.
+      # blocking failure. Baseline: PASS — 0 blocking, 0 advisory.
       - name: Curriculum validation
         run: node validate.mjs
 
@@ -28,7 +28,35 @@ jobs:
       - name: Typecheck
         run: npm run typecheck
 
+      # The sync round-trip needs a real Postgres and a running server, so a
+      # fake would not exercise the change_seq trigger, the last-write-wins
+      # upsert, or cursor paging — which is where sync actually goes wrong.
+      - name: Start Postgres
+        run: |
+          docker run -d --name hankan-pg \
+            -e POSTGRES_PASSWORD=test -e POSTGRES_DB=hankan \
+            -p 55432:5432 postgres:16-alpine
+          for i in $(seq 1 30); do
+            docker exec hankan-pg pg_isready -U postgres -d hankan && break
+            sleep 1
+          done
+
+      - name: Start the sync server
+        env:
+          DATABASE_URL: postgres://postgres:test@localhost:55432/hankan
+          HANKAN_TOKEN: test-token
+          HANKAN_TEST_MODE: "1"
+          PORT: "8788"
+        run: |
+          node --experimental-strip-types server/src/main.ts &
+          for i in $(seq 1 30); do
+            curl -sf http://localhost:8788/health && break
+            sleep 1
+          done
+
       - name: Tests
+        env:
+          HANKAN_TEST_SERVER: http://localhost:8788
         run: npm test
 
       # Every word in every unit's words[] must resolve in lemma or surface.