v2.0.0

What's New

• Add transceiver audio source with Hamlib CAT control via rigctld
• Add KiwiSDR auto-reconnect with exponential backoff (max_retries, retry_delay config options)
• Add unit tests for grammar, DX cluster, POTA spotter, and transceiver modules
• Fix duplicate words in Vosk grammar vocabulary
• Remove unused imports and deleted sound_card source