[jkramer5103]

Notifications from native applications without a tracked PID/window can still use a generic icon even after e225755: Source._getApp() only resolves the desktop-entry hint through the Flatpak-only application table. Resolve the desktop-file ID first, accepting hints with or without .desktop, then retain the existing Flatpak, browser-alias, name and tray fallbacks. PID matches retain priority.

Related to #14070. This addresses the remaining native-app lookup case; it does not duplicate the app-icon fallback already on master or claim to reproduce every reported Slack/Geary notification.

The standalone test was removed from the PR at the maintainer's request. The final diff contains only the eight-line source change.

Validation performed locally before removing the test:

• node tests/unit/notificationDaemon.js passes against the real module with GI/UI boundaries stubbed. Covers native desktop hints, source and notification icons, explicit icon priority, PID precedence, Flatpak IDs/browser aliases, unique/ambiguous names, unknown/missing hints, urgency icons and tray lookup.
• The same test against unchanged upstream fails at the first native-app identity assertion (null instead of the native app).
• node --check js/ui/notificationDaemon.js and git diff --cached --check pass. Staged diff reviewed and scanned for common credential patterns.
• Test processes ran in a verified systemd cgroup with memory.max=1073741824 and memory.swap.max=0, one process at a time.

Limitations: the local standalone proof is not included in the submitted changes. No full build, real GI/CJS session, D-Bus integration test or live UI screenshots; Cinnamon/CJS and a desktop session are unavailable in this environment. Visual behavior remains unverified.

[mtwebster]

Please don't include tests

[jkramer5103]

Removed the standalone test in 55f2ada. The PR now contains only the eight-line notification lookup change; the description retains the local validation results.