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.

docker-compose.local-domain.dev.yml

@@ -0,0 +1,20 @@
+# Dev override for tesla-roadtrip.test
+services:
+  app:
+    build:
+      target: development
+    command: ["npm", "run", "dev"]
+    volumes:
+      - ./server:/app/server
+      - ./prisma:/app/prisma
+    labels: !reset {}
+  frontend:
+    build:
+      target: development
+    command: ["npm", "run", "dev"]
+    volumes:
+      - ./client:/app/client
+    labels:
+      - "caddy=tesla-roadtrip.test"
+      - "caddy.reverse_proxy=/api/* app:3000"
+      - "caddy.reverse_proxy=/* {upstream http://frontend:5173}"