feat(drone): add personal drone with first-person camera and control panel

Implements a flyable quadcopter with WASD/arrow controls, altitude hold,
and landing. Features a scissored camera view in a command panel showing
real-time feed, telemetry, and control hints. Includes localized strings
for English, Spanish, and Portuguese.

lang/en.json

@@ -221,6 +221,8 @@
     "city.beach_active": "Relaxing at the beach",
     "city.atc_missing": "No control tower configured.",
     "city.port_missing": "No port authority configured.",
+    "city.drone": "Drone",
+    "city.drone_hint": "WASD fly · ↑↓ up/down · ←→ turn · Space up · C down · Q to land",
     "city.sign_plaza": "Plaza",
     "city.sign_beach": "Beach",
     "city.sign_food": "Food",