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

utils/__init__.py

@@ -19,7 +19,6 @@ from .logging import (
     bluetooth_logger,
     adsb_logger,
     satellite_logger,
-    iridium_logger,
 )
 from .validation import (
     escape_html,