chore(ci): adapt more docker steps

.github/workflows/main-docker.yml

@@ -56,12 +56,12 @@ jobs:
         run: npx playwright install --with-deps
 
       - name: Run the TypeScript build
-        run: npm run build
+        run: npm nx run @triliumnext/server:build
 
       - name: Build and export to Docker
         uses: docker/build-push-action@v6
         with:
-          context: .
+          context: apps/server
           file: ${{ matrix.dockerfile }}
           load: true
           tags: ${{ env.TEST_TAG }}