Adapt for self-hosted deployment on Coolify

- Replace @vercel/postgres with standard pg library
- Add Dockerfile for Next.js standalone build
- Add tsconfig.json, postcss.config.js
- Fix globals.css undefined tailwind utilities
- Force dynamic rendering for DB-dependent pages
- Add .dockerignore

frontend/postcss.config.js

@@ -0,0 +1,6 @@
+module.exports = {
+  plugins: {
+    tailwindcss: {},
+    autoprefixer: {},
+  },
+}