Fix repeated update notifications after dismiss

[anod]

Summary

• mark update notifications viewed when the Dismiss action is used
• add a delete intent so swiping a notification away also marks updates viewed
• add a regression test for notification action read-state mapping

Validation

• .\gradlew.bat :app:testDebugUnitTest
• .\gradlew.bat :app:ktlintMainSourceSetCheck :app:ktlintTestSourceSetCheck

Note: full .\gradlew.bat ktlintCheck is blocked by a pre-existing final-newline violation in app\build.gradle.kts.

[Copilot]

Pull request overview

Fixes a bug where update notifications kept reappearing after the user dismissed them. Dismissal (via the action button or by swiping the notification away) now marks updates as viewed, matching the behavior already triggered when the watchlist is opened.

Changes:

• NotificationActivity now centralizes notification-action constants at top level and uses a shouldMarkUpdatesViewed() helper so the dismiss action also flips prefs.isLastUpdatesViewed = true.
• SyncNotification adds a setDeleteIntent(...) routing swipe-aways through NotificationActivity with ACTION_DISMISS, and consolidates pending-intent creation via a small markViewedPendingIntent helper.
• New unit test NotificationActivityTest covers the action-type → mark-viewed mapping.

Reviewed changes

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

File	Description
app/src/main/java/com/anod/appwatcher/NotificationActivity.kt	Adds top-level action constants and shouldMarkUpdatesViewed; dismiss now marks updates viewed.
app/src/main/java/com/anod/appwatcher/sync/SyncNotification.kt	Adds delete intent for swipe-dismiss and consolidates pending intent creation.
app/src/test/java/com/anod/appwatcher/NotificationActivityTest.kt	New unit test for action-type to mark-viewed mapping.