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/src/styles/globals.css

@@ -0,0 +1,51 @@
+@tailwind base;
+@tailwind components;
+@tailwind utilities;
+
+:root {
+  --tesla-red: #E82127;
+  --bg: #0a0a0a;
+  --bg-elevated: #111111;
+  --bg-card: #1a1f2b;
+  --border: rgba(255, 255, 255, 0.08);
+}
+
+body {
+  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
+  background-color: var(--bg);
+  color: white;
+}
+
+/* Tesla-inspired scrollbar */
+::-webkit-scrollbar {
+  width: 6px;
+  height: 6px;
+}
+::-webkit-scrollbar-track {
+  background: #1a1a1a;
+}
+::-webkit-scrollbar-thumb {
+  background: #3a3a3a;
+  border-radius: 3px;
+}
+::-webkit-scrollbar-thumb:hover {
+  background: #E82127;
+}
+
+/* Map container */
+.leaflet-container {
+  background: #0a0f1a !important;
+}
+
+/* Chat bubbles */
+.chat-bubble-user {
+  background: #E82127;
+  color: white;
+  border-bottom-right-radius: 4px;
+}
+
+.chat-bubble-assistant {
+  background: #1f242e;
+  border: 1px solid rgba(255,255,255,0.08);
+  border-bottom-left-radius: 4px;
+}