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/postcss.config.mjs

@@ -0,0 +1,5 @@
+const config = {
+  plugins: ["@tailwindcss/postcss"],
+};
+
+export default config;