Component system

[john-]

Title

feat: introduce modular component architecture, event dispatching, and Silero VAD

Summary

This PR refactors ham2mon's audio processing pipeline into an extensible, decoupled Component Architecture (WavGatekeeper for audio evaluation and TransmissionNotifier for event listeners), centralizes WAV recording persistence within Scanner, and adds Silero VAD voice detection.

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Key Changes

• Extensible Component Architecture (apps/components/):

  • BaseComponent: Foundation for components with strict lifecycles (start, stop, error recovery).
  • ComponentManager: Orchestrates worker pools, isolates timeouts, and prevents single-component crashes from hanging the scanner loop.
  • Built-in WavGatekeeper components:
    • TfliteClassifierComponent: Refactored existing TFLite/LiteRT model runner into an isolated component process.
    • SileroVadComponent: Added lightweight ONNX-based Silero Voice Activity Detection (~16MB runtime dependency).
  • Built-in TransmissionNotifier components:
    • ActivityLoggerComponent: Dispatches kept transmission records to active channel activity loggers.

• Audio Recording Lifecycle Centralization:

  • Moved WAV file retention, metadata formatting, and sidecar JSON generation from demodulators/receiver directly into Scanner._process_completed_transmission().
  • Introduced immutable @dataclass(frozen=True) TransmissionRecord for cross-boundary payload safety.

• Configuration Alignment & Docs:

  • Added structured components: domain block parsing to MasterHam2MonConfig and CLI options.
  • Added user documentation (doc/components/available_components.md) and updated README.md and doc/minimal.config.yaml.
  • Added test coverage for component lifecycle, gatekeeper evaluations, and notifier dispatches.