Scaffold MobBridge audio output probe methods (Mob.Audio.output_status/level)

[GenericJam]

What

Scaffolds the app-owned Kotlin bridge methods backing mob's audio output probes (GenericJam/mob#54):

• audioOutputStatus(): FloatArray — volume / mute / route / other-audio via AudioManager, as float[4].
• audioOutputLevel(source): FloatArray — peak/RMS dB from a short-lived Visualizer on Mob.Audio's own player session (audioPlayer.audioSessionId), which works with RECORD_AUDIO. Returns a length-1 error code (1 unsupported / 2 needs_record_audio / 3 not_playing) the NIF maps to an atom.

Why not session 0 (global mix)

The first cut tapped session 0 to observe foreign audio. Device testing (moto g power 2021, Android 11) showed a session-0 Visualizer fails with ERROR_NO_INIT even with RECORD_AUDIO + MODIFY_AUDIO_SETTINGS — global output capture is privileged. So audioOutputLevel meters only the app's own player session; global device-audio capture moves to a separate MediaProjection-based plugin (test-env dep).

Tests

• ktlint clean (mix test --only lint generates a project and lints the real Kotlin).
• Template test asserts the own-session tap (audioPlayer?.audioSessionId) and that session 0 is not used.

Merge alongside GenericJam/mob#54.

🤖 Generated with Claude Code

[GenericJam]

Review — approve (scaffold half of the output probes)

The generated MobBridge methods (audioOutputStatus(): FloatArray, audioOutputLevel(String): FloatArray) match the zig cached-method descriptors and the mob #54 NIF arities exactly — FFI seam is clean. The template test asserts the own-session tap (audioPlayer?.audioSessionId) and refute Visualizer(0), which guards against the privileged-session regression — good.

Merge alongside mob #54 (this is its Android half). The mob side uses cacheOptional + null-guards, so an app that updates mob before regenerating its bridge no-ops gracefully rather than crashing — but for the Android probes to actually work, existing apps must regenerate MobBridge.kt from this template. Worth a line in the merge/release notes.

Two follow-ups tracked on mob #54 apply here: the Android Visualizer floor is -96 dB (so Mob.Audio's :silent at -120 never triggers on Android), and mapping all measurement failures to needs_record_audio can mislead callers about a permission issue when there isn't one.