feat: show server version in sidebar header

Version injected at build time via VITE_APP_VERSION env var.
CI sets it to branch@sha. Falls back to 'dev' in local dev.
Displayed next to "Cameleer" in the sidebar header.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitea/workflows/ci.yml

@@ -53,6 +53,7 @@ jobs:
           npm run build
         env:
           REGISTRY_TOKEN: ${{ secrets.REGISTRY_TOKEN }}
+          VITE_APP_VERSION: ${{ github.ref_name }}@${{ github.sha }}
 
       - name: Build and Test
         run: mvn clean verify -DskipITs -U --batch-mode