Add landing page, Docker setup, and CI/CD pipeline

React + Vite + TypeScript + Tailwind frontend with landing page,
Docker Compose for dev and prod (nginx-proxy integration),
and Gitea Actions workflow for automated deployment.

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

frontend/vite.config.ts

@@ -0,0 +1,13 @@
+import { defineConfig } from 'vite';
+import react from '@vitejs/plugin-react-swc';
+import tailwindcss from '@tailwindcss/vite';
+import path from 'path';
+
+export default defineConfig({
+  plugins: [react(), tailwindcss()],
+  resolve: {
+    alias: {
+      '@': path.resolve(__dirname, './src'),
+    },
+  },
+});