Fix Xiaomi haptic feedback crash

[rosuH]

Summary

• Add android.permission.VIBRATE so Xiaomi/Android 16 haptic feedback paths can reach the vibrator service safely.
• Guard View.performHapticFeedback against SecurityException and make the existing haptic cooldown effective.
• Add a regression test for denied haptic permission handling.

Release note

• Fixed a Xiaomi/Android 16 haptic feedback crash reported by A**** K***.

Test plan

• ./gradlew :app:testDebugUnitTest :app:assembleRelease

[Copilot]

Pull request overview

This PR fixes a haptic feedback crash path by declaring vibration permission and safely handling denied haptic feedback calls while preserving cooldown behavior.

Changes:

• Adds android.permission.VIBRATE to the app manifest.
• Wraps haptic feedback execution in a SecurityException guard.
• Adds unit coverage for denied permission and delegate return behavior.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
app/src/main/AndroidManifest.xml	Declares vibration permission required by haptic feedback paths.
app/src/main/java/me/rosuh/easywatermark/utils/VibrateHelper.kt	Adds safe haptic feedback execution and makes cooldown timestamp updates effective.
app/src/test/java/me/rosuh/easywatermark/utils/VibrateHelperTest.kt	Adds regression tests for the safe haptic feedback helper.

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