fix: hold gesture on Kept stat card, haptic refinement & thumbnail preview reload fix

[ShubhamJ010]

What does this PR do?

This PR addresses several UI, gesture, and preview interaction fixes:

1. Thumbnail Preview Reload Fix: Fixed an issue in ScreenshotPreviewOverlay where LaunchedEffect was keyed solely on uri, preventing bitmap reloads on repeated hold attempts on the same thumbnail after the previous preview bitmap was disposed. Now keyed on (uri, visible).
2. Kept Stat Card Hold Gesture: Requires a hold gesture on the Kept stat card to toggle the SHOWN state and reveal the Kept screenshots list.
3. Pull-to-Reveal Haptics Refinement: Removed the drag tick haptic feedback during pull-to-reveal gestures to keep haptics focused on trigger limits.
4. UI & Color Compositing: Composited card container colors and applied overscroll & rendering stability adjustments.

Related issue

None

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that changes existing behavior)
• Refactor / chore / docs

How has this been tested?

• ./gradlew lint
• ./gradlew test
• Manual verification on device/emulator (API level: 34 / Android 14)

Checklist

• My code follows the project style and builds cleanly
• I have added/updated tests where appropriate
• I have updated CHANGELOG.md (for user-facing changes)