[FEATURE] Native volume key / Bluetooth shutter shortcut for FadShot during video recording

[dedtsss]

Feature request

Please add a native hotkey option to capture a still photo / FadShot while video recording is active, using Volume Up and/or Volume Down.

Use case

FadCam can already capture photos while a recording is in progress, and recent code also appears to include FadShot app shortcuts (capture_photo / capture_photo_front). However, for dashcam, bodycam, helmet-mounted, tripod, or other hands-free recording scenarios, it would be very useful to trigger photo capture directly from hardware keys or a small Bluetooth shutter remote.

Many inexpensive Bluetooth camera remotes send volume key events (KEYCODE_VOLUME_UP / KEYCODE_VOLUME_DOWN). This would allow the user to save an important still frame without touching the phone screen.

Requested behavior

• Add a setting such as: Volume Up action / Volume Down action.
• Available action: Capture photo / FadShot while recording.
• Ideally support both back and front photo actions, or at least use the currently selected/active camera.
• Support Bluetooth shutter remotes that emit Android volume key events.
• Keep the behavior configurable, so it does not conflict with normal system volume control.
• If direct key capture is not reliable in all app states on some Android versions, please document the limitation and keep the existing app shortcut approach as a fallback.

Why this is useful

This would make FadCam more practical as a dashcam/bodycam-style recorder: video keeps running continuously, and the user can mark important moments by saving a photo from a physical button or Bluetooth remote.

Related context

Issue #96 already discussed using FadCam shortcuts with key-mapping apps. This request is narrower: native in-app support for Volume Up / Volume Down or Bluetooth shutter buttons specifically for taking FadShot photos during active video recording.