fix(notify): register Windows AppUserModelID so toasts appear (#3)

[karem505]

Fixes #3 — Windows 11 toast notifications never appear for the installed app.

Root cause

On an installed build, tauri-plugin-notification sets the toast's System.AppUserModel.ID to the bundle identifier (com.karem.whatrust) — see tauri-plugin-notification desktop.rs (notification.app_id(&self.identifier)), only on installed builds (in dev it uses the always-registered PowerShell AUMID, which is why notifications work under cargo run but break once installed).

A WinRT toast only renders if that AUMID is registered on the system. Tauri's NSIS/MSI installers do tag their Start-Menu shortcut with the AUMID, but that registration is fragile and can be ineffective at toast-time:

• the Desktop shortcut carries no AUMID property (only the Start-Menu one does),
• a per-user vs per-machine install-path mismatch,
• a regenerated/repaired shortcut that dropped the property,
• or running the raw .exe.

When the AUMID isn't registered, CreateToastNotifierWithId/Show fails — and that error was swallowed at three layers (notify::show's let _ =, the notify command's unit return, and bridge.js's empty .catch()). Net effect: no toast and nothing logged — exactly the reporter's "payload never reaches Action Center, no drop logs" symptom.

Fix

At startup (aumid::register, Windows-only, per-user, no admin, idempotent):

1. Write HKCU\Software\Classes\AppUserModelId\<identifier> with a DisplayName — this registers the AUMID so the Action Center renders toasts for an unpackaged desktop app, independent of installer or launch path. Re-written each launch, so a shortcut that lost its AUMID self-heals.
2. Call SetCurrentProcessExplicitAppUserModelID(<identifier>) to pin the process to the same AUMID.

The AUMID is read from the live Tauri config identifier (the same value the plugin passes to app_id()), so the two can't drift apart. The #[cfg(windows)] body compiles to a no-op on Linux/macOS.

Also: notify::show now logs the notification Result instead of discarding it, so any residual failure is diagnosable from the console.

Testing

• cargo check/clippy/test --locked on Linux — pass (48 tests).
• The exact #[cfg(windows)] module + the three new windows crate features (Win32_Security, Win32_System_Registry, Win32_UI_Shell) cross-compile clean for x86_64-pc-windows-gnu (verified in isolation) — CI's windows-latest job is the full gate.
• Headless runtime boot: app starts, windows render, no panic in setup().
• ⚠️ The toast actually rendering on Windows 11 needs confirmation on a real Win11 box (can't be exercised from Linux) — see the verification steps posted on Notification Doesn't Appear #3.

🤖 Generated with Claude Code