feat: pause media playback while recording

[cwillison94]

Why

When using push-to-talk dictation, any music or video already playing keeps going during the recording.
It bleeds into the mic and is distracting, and there is currently no way to have it pause automatically.

This adds an opt-in setting that pauses whatever is playing when a recording starts and resumes it when the recording ends.
It is off by default, so existing behavior is unchanged unless a user turns it on in Settings > Recording.

How it works

Pause and resume use discrete commands, never a play/pause toggle.
This matters because the obvious toggle-based approach (simulating the hardware media key, gated on a CoreAudio "output device is running" check) starts paused audio on record-start: browsers and YouTube keep the output device running even while paused, so the check false-positives and the toggle resumes playback the user had deliberately paused.

Discrete pause/play needs the private MediaRemote framework, which macOS 15.4+ restricts to Apple platform binaries.
An app calling it directly just gets empty/false state back (verified on macOS 26).
So a small helper dylib (MediaRemoteHelper/OSWMediaRemote.swift, ~90 lines, no third-party dependency) is loaded through /usr/bin/perl (a platform binary) via osw-media-remote.pl; it reads the real Now Playing state and sends kMRPlay / kMRPause.
Because the helper runs inside perl's entitled process, it gets accurate state and its commands take effect.
A discrete pause is a no-op when nothing is playing, so recording can never start audio that was not already playing, and play is only ever sent to resume media this feature paused.

It stays player-agnostic (Spotify, Apple Music, Safari/Chrome/YouTube, etc.) with no per-app scripting.
The helper is built by run.sh / notarize_app.sh and embedded in Contents/Frameworks (loaded out-of-process by perl, never linked into the app), with the launcher bundled in Contents/Resources.
It hooks into AudioRecorder, the single choke point for every trigger mode (keyboard shortcut, single modifier, mouse button, hold-to-record, double-tap), with all subprocess work on a dedicated serial queue so it never delays audio capture, guarded by a timeout, and failing safe (doing nothing) if the helper is ever unavailable.

Testing

Built and run on macOS 26 (Apple Silicon).
Verified the helper end to end through perl (reads playing/paused state, sends discrete pause/play, and pausing an already-paused player is a no-op), and verified in-app that recording pauses playback on start and resumes on release when media is playing, while starting a recording with media already paused issues no command and leaves it paused.

Known limitation

If the user manually resumes playback during a recording, stopping the recording will still issue a resume.
Discrete commands make misbehavior far less likely than the old toggle, but true fade in/out is out of scope.

🤖 Generated with Claude Code

[cwillison94]

It introduces a new setting which is currently defaulting to off (though arguable should be on)