REFACTOR(repo): simplify project structure

- Move services/nextjs/ to nextjs/
- Move Dockerfile.prod to Dockerfile at root
- Remove deploy/ folder (K8s manifests moved to K3S-HOME/web-apps)
- Remove .gitea/ workflows
- Update GitHub Actions for new structure
- Remove develop branch triggers

nextjs/providers/theme-provider.tsx

@@ -0,0 +1,16 @@
+'use client';
+
+import dynamic from 'next/dynamic';
+import { ThemeProviderProps } from 'next-themes';
+
+const NextThemesProvider = dynamic(
+  () => import('next-themes').then((e) => e.ThemeProvider),
+  {
+    ssr: false,
+  }
+);
+
+export function ThemeProvider({ children, ...props }: ThemeProviderProps) {
+  return <NextThemesProvider {...props}>{children}</NextThemesProvider>;
+}
+