fix(ci): use monorepo-filtered commands in Gitea CI (GRO-1522)

The root pnpm scripts typecheck/lint/test the stale src/ directory.
Use pnpm --filter @groombook/api to target the correct apps/api/ path,
matching the GitHub Actions CI configuration.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

.gitea/workflows/ci.yml

@@ -32,10 +32,10 @@ jobs:
         run: pnpm install --frozen-lockfile
 
       - name: Typecheck
-        run: pnpm typecheck
+        run: pnpm --filter @groombook/api typecheck
 
       - name: Lint
-        run: pnpm lint
+        run: pnpm --filter @groombook/api lint
 
   test:
     name: Test
@@ -56,7 +56,7 @@ jobs:
         run: pnpm install --frozen-lockfile
 
       - name: Run tests
-        run: pnpm test
+        run: pnpm --filter @groombook/api test
 
   docker:
     name: Build & Push Docker Images