ci: migrate Docker images to GHCR and add tag-triggered release

- Replace Docker Hub with GitHub Container Registry (ghcr.io)
- Add tag push trigger for automatic release creation
- Dynamic version from tag name (2.0.8 format)
- Frontend GitHub links now use env variable VITE_GITHUB_REPO
- Release artifacts auto-replace repo/version in scripts

vite-frontend/src/layouts/admin.tsx

@@ -311,7 +311,7 @@ export default function AdminLayout({
             <p className="text-xs text-gray-400 dark:text-gray-500">
               Powered by{' '}
               <a 
-                href="https://github.com/bqlpfy/flux-panel" 
+                href={siteConfig.github_repo}
                 target="_blank" 
                 rel="noopener noreferrer"
                 className="text-gray-500 dark:text-gray-400 hover:text-gray-600 dark:hover:text-gray-300 transition-colors"