feat: update OpenSky API integration and improve flight tracking

- Increased max duration for flight data requests from 10 to 30 seconds.
- Adjusted fetch timeouts and cache TTL to enhance performance.
- Implemented snapping of bounding box coordinates to a grid for better cache sharing.
- Enhanced flight data fetching logic to adapt polling intervals based on remaining API credits.
- Introduced a new adaptive polling mechanism with different tiers based on credit usage.
- Updated flight layers animation duration for smoother transitions.
- Added a new slider component for orbit speed control in the UI.
- Refactored flight card positioning logic to ensure it remains within viewport bounds.
- Improved control panel layout for better mobile usability.
- Adjusted default orbit speed settings for a more user-friendly experience.

.env.example

@@ -12,4 +12,7 @@ OPENSKY_CLIENT_SECRET=
 # OPTION 2: Basic Auth (Legacy accounts only)
 # Deprecated — will be removed. Only works for accounts created before March 2025.
 # OPENSKY_USERNAME=
-# OPENSKY_PASSWORD=
+# OPENSKY_PASSWORD=
+
+# ─── Analytics (optional) ─────────────────────────────────────────────────────
+# NEXT_PUBLIC_GA_ID=G-XXXXXXXXXX