fix(ci): switch tests from VPS host runner to NAS ubuntu-latest

The VPS runner's host executor has a bug where completion callbacks
are silently dropped, causing jobs to appear stuck. Switched backend
and frontend tests to the NAS runner which correctly reports status.

Also updated checkout URL to use Docker bridge gateway 172.21.0.1:3300.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.gitea/workflows/deploy.yml

@@ -14,7 +14,7 @@ concurrency:
 jobs:
   backend-tests:
     name: Backend Tests
-    runs-on: vps
+    runs-on: ubuntu-latest
     env:
       SECRET_KEY: test-secret-key-for-ci-environment-32chars-minimum
 
@@ -22,7 +22,7 @@ jobs:
       - name: Checkout repository
         run: |
           if [ ! -d .git ]; then
-            git clone --depth=1 "http://100.78.131.124:3300/${GITHUB_REPOSITORY}.git" .
+            git clone --depth=1 "http://172.21.0.1:3300/${GITHUB_REPOSITORY}.git" .
           fi
 
       - name: Setup Python