chore: initial checkpoint - Tesla Roadtrip planner

- Proactive Grok integration (xAI API + local CLI fallback)
- Real road routing via OSRM (no more bird's-eye lines)
- Heavy structured logging for fast iteration
- Strong sanitization + geocoding + ErrorBoundary (no black screens)
- Playwright E2E tests (API diagnostic + full UI flow)
- scripts/dev.sh for one-command startup
- Clean .env.example + documentation

This is a stable checkpoint before further prompt/UI refinement.

client/tailwind.config.js

@@ -0,0 +1,21 @@
+/** @type {import('tailwindcss').Config} */
+export default {
+  content: [
+    "./index.html",
+    "./src/**/*.{js,ts,jsx,tsx}",
+  ],
+  darkMode: 'class',
+  theme: {
+    extend: {
+      colors: {
+        tesla: {
+          red: '#E82127',
+          black: '#0a0a0a',
+          dark: '#111111',
+          gray: '#1a1f2b',
+        }
+      }
+    },
+  },
+  plugins: [],
+}