chore(ci, dto): update build workflow and enhance post DTOs

- Added NODE_NO_WARNINGS environment variable to build and deploy workflows.
- Upgraded actions/upload-artifact and actions/download-artifact to version 4 in the build workflow.
- Introduced ContentEditedAt field in PostResponse and PostDetailResponse DTOs to track content modification timestamps.
- Updated post conversion functions to include ContentEditedAt in responses.
- Ensured ContentEditedAt is set during post updates in the repository.

.gitea/workflows/build.yml

@@ -47,7 +47,7 @@ jobs:
         run: go build -v -o server ./cmd/server
 
       - name: Upload artifacts
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: backend-server-linux-amd64
           path: server
@@ -70,7 +70,7 @@ jobs:
           password: ${{ secrets.GIT_TOKEN }}
 
       - name: Download artifact
-        uses: actions/download-artifact@v3
+        uses: actions/download-artifact@v4
         with:
           name: backend-server-linux-amd64