ci: fix quality job working-directory and adjust timeouts

working-directory wasn't being honored for npm steps in the quality
job. Switch to explicit cd frontend && commands.

Reduce race timeout from 300s to 240s.

.gitea/workflows/ci.yaml

@@ -102,7 +102,7 @@ jobs:
 
       - name: Test with race detector
         working-directory: backend
-        run: go test -tags "test,dev" -race -count=1 -timeout 300s ./...
+        run: go test -tags "test,dev" -race -count=1 -timeout 240s ./...
         env:
           POSTGRES_HOST: postgres
           TEST_DB_HOST: postgres
@@ -132,11 +132,12 @@ jobs:
           node-version: "22"
 
       - name: Frontend type check
-        working-directory: frontend
         run: |
+          cd frontend
           npm ci
           npm run check
 
       - name: Frontend lint
-        working-directory: frontend
-        run: npm run lint
+        run: |
+          cd frontend
+          npm run lint