fix(ci): wait for Mongo via docker exec mongosh, not nc

The Forgejo runner image doesn't ship netcat — 30 retries of
'sh: 1: nc: not found' just burned the timeout. Use mongosh from
inside the container; no host-side tooling needed.

.forgejo/workflows/test.yml

@@ -44,7 +44,7 @@ jobs:
           docker run -d --name mongo-ci --network host mongo:7
           docker ps
       - name: Wait for MongoDB
-        run: timeout 30 sh -c 'until nc -z localhost 27017; do sleep 1; done'
+        run: timeout 30 sh -c 'until docker exec mongo-ci mongosh --quiet --eval "1" >/dev/null 2>&1; do sleep 1; done'
       - name: MongoDB log on failure
         if: failure()
         run: docker logs mongo-ci || true
@@ -107,7 +107,7 @@ jobs:
           docker run -d --name mongo-ci --network host mongo:7
           docker ps
       - name: Wait for MongoDB
-        run: timeout 30 sh -c 'until nc -z localhost 27017; do sleep 1; done'
+        run: timeout 30 sh -c 'until docker exec mongo-ci mongosh --quiet --eval "1" >/dev/null 2>&1; do sleep 1; done'
       - name: MongoDB log on failure
         if: failure()
         run: docker logs mongo-ci || true