feat(frontend): add React dashboard with TypeScript

Add modern React frontend to replace Streamlit dashboard:
- Vite build system with TypeScript
- Tailwind CSS for styling
- Component structure in src/
- Production Dockerfile with nginx
- Development server on port 5173

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/tailwind.config.js

@@ -0,0 +1,32 @@
+/** @type {import('tailwindcss').Config} */
+export default {
+  content: [
+    "./index.html",
+    "./src/**/*.{js,ts,jsx,tsx}",
+  ],
+  theme: {
+    extend: {
+      colors: {
+        primary: {
+          DEFAULT: '#6366f1',
+          dark: '#4f46e5',
+        },
+        secondary: '#0ea5e9',
+        success: '#10b981',
+        warning: '#f59e0b',
+        error: '#ef4444',
+        bg: {
+          dark: '#0f172a',
+          card: '#1e293b',
+          'card-hover': '#334155',
+        },
+        text: {
+          primary: '#f8fafc',
+          secondary: '#94a3b8',
+        },
+        border: '#334155',
+      },
+    },
+  },
+  plugins: [],
+}