Remove Iridium (demo-only) and add version display

- Remove Iridium satellite decoding feature (was placeholder/demo only)
  - Delete routes/iridium.py
  - Remove Iridium UI elements from index.html
  - Remove Iridium CSS styles
  - Remove Iridium dependencies and logger
  - Clean up SDR docstrings mentioning Iridium

- Add version number display (fixes #31)
  - Add VERSION constant to config.py
  - Add --version / -V CLI flag to intercept.py
  - Display version badge in web UI header

docs/FEATURES.md

@@ -41,7 +41,6 @@ Complete feature list for all modules.
 - **Celestrak integration** - fetch by category (Amateur, Weather, ISS, Starlink, etc.)
 - **Next pass countdown** - time remaining, visibility duration, max elevation
 - **Telemetry panel** - real-time azimuth, elevation, range, velocity
-- **Iridium burst detection** monitoring (demo mode)
 - **Multiple satellite tracking** simultaneously
 
 ## WiFi Reconnaissance

docs/USAGE.md

@@ -90,7 +90,6 @@ The system highlights aircraft transmitting emergency squawks:
 4. **View Sky Plot** - Polar plot shows satellite positions in real-time
 5. **Ground Track** - Map displays satellite orbit path and current position
 6. **Full Dashboard** - Click "Full Screen Dashboard" for dedicated satellite view
-7. **Iridium Mode** - Switch tabs to monitor for Iridium burst transmissions
 
 ### Adding Satellites from Celestrak