What changed

AirPods "Conversational Awareness" can now drive a reaction in CAPod: when you start speaking, it can automatically lower the media volume (by an amount you choose) or pause playback, and restores it when you stop. It's opt-in per device and off by default, found under Reactions once Conversational Awareness is enabled. On Android the AirPods don't lower the volume on their own — this fills that gap.

Technical Context

• The pods already push a speaking-detection event (the same signal behind Apple's own volume ducking); it was decoded but never acted on. On Android the firmware doesn't duck audio itself, so the reaction runs app-side.
• The speaking status is the last byte of the 0x4B frame ({1,2} = started, {6,8,9} = stopped, others = keep-alive); confirmed against real AirPods Pro 3 captures and the librepods project. The earlier assumption read the wrong byte, which is why it never fired.
• Disengage happens on the stop event, with a frame-idle stale timeout as a fallback if a stop is dropped, plus cleanup on disconnect and service stop. Volume is restored unconditionally to the pre-duck level so it doesn't ratchet down when another app also moves the volume.
• AAP-only: requires bonded pods with an active session and the device-side Conversational Awareness setting on — the action picker only appears once it's enabled.

Review checklist

• Status-byte mapping {1,2}/{6,8,9} for models other than Pro 3 (only Pro 3 was tested on-device)
• Unconditional volume restore vs. respecting a deliberate mid-conversation volume change

Closes #581