Functionality camera and pause

[Gavalencia12]

<=========== PULL REQUEST TEMPLATE ===========>

Pull Request Title

Add Camera Toggle, Zoom Gesture, and Pause Functionality to translator_screen
#40

Description

• The translator_screen now supports switching between front and rear cameras using a new camera toggle button.
• A pinch-to-zoom feature has been implemented to allow users to zoom in/out during hand tracking.
• The existing pause button has been fully implemented, allowing users to pause and resume the interpretation process without resetting the session.
• These changes were necessary to improve user experience, precision in hand tracking, and overall control of the interpreter screen.
• Manual testing was performed on Android to ensure correct camera flipping, smooth zoom behavior, and proper pause/resume functionality.

List of Changes

1. Added _isPaused state and full pause/resume logic.
2. Implemented camera flip functionality using CameraService.flipCamera().
3. Added pinch-to-zoom gesture with zoom clamped to min/max device limits.
4. Updated CameraService with setZoom() and zoom level getters.
5. Reset zoom levels when switching cameras.
6. Updated UI to include new camera buttons and structured them properly.
7. Improved internal timer handling for detection delays and cooldown.
8. Minor refactors to improve readability and avoid detection while paused.

Additional Information

Before

Desactive Camera	Active Camera

After

Front Camera	Rear Camera

Checklist

• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.

[mpegueros]

LGTM 👍