All major TX parameters are now hot-swappable during transmission:
- DSP params (drive, stereo, pilot, RDS levels, limiter) via
atomic.Pointer[LiveParams], loaded once per chunk (~50ms)
- RDS text (PS, RT) via atomic.Value in encoder, applied at
RDS group boundaries (~88ms)
- TX frequency via driver.Tune(), applied between chunks
Zero locks in DSP path. HTTP handler writes atomics, run loop
reads them. Validation happens before store.
New: SoapyDriver.Tune() for live frequency changes.
New: LiveConfigUpdate/LivePatch types for type-safe patching.
New: 4 engine tests for live DSP/freq/RDS updates + validation.
