fix: prevent video corruption from rapid hide/unhide clicks

[Ahmed-Hekal-01]

Fixes critical race condition when clicking hide button 2 times quickly.

Changes:

• Add mIsTogglingVisibility flag to track ongoing visibility toggle operations
• Check flag in click listener to prevent concurrent operations
• Clear flag in callback when operation completes

This ensures only one hide/unhide operation runs at a time, preventing the race condition that corrupted video files.

Tested on Samsung A24, Android 16.

Type of change(s)

• Bug fix
• Feature / enhancement
• Infrastructure / tooling (CI, build, deps, tests)
• Documentation

What changed and why

• Fixed critical bug where rapidly clicking hide/unhide button corrupted video files
• Added concurrency control to prevent race condition during file rename operations
• File corruption resulted in 0 byte size, 00:00 duration, and "unsupported format" errors

Tests performed

• Tested rapid clicking (2+ clicks) on hide button with videos - no corruption occurs
• Verified both bottom action button and menu items work correctly
• Tested on Samsung A24, Android 16
• Confirmed fix prevents race condition while maintaining normal hide/unhide functionality

Before & after preview

Before: Clicking hide button twice quickly corrupts the video file

Video shows: 0 bytes size, 00:00 duration, "unsupported format" error

After: Multiple clicks are safely ignored while operation is in progress, file remains intact

Closes the following issue(s)

N/A - Critical production bug fix (allowed without prior issue per contribution guidelines)

Checklist

• I read the contribution guidelines.
• I manually tested my changes on device/emulator (if applicable).
• I updated the "Unreleased" section in CHANGELOG.md (if applicable).
• I have self-reviewed my pull request (no typos, formatting errors, etc.).
• I understand every change in this pull request.