Related: #3148 (sidebar Delete shortcut).

Summary

After the editor page remounts, one Delete / macOS Fn+Backspace can open two trash confirmation dialogs. app.vue registered sidebar bus handlers on every mount, but never removed them. The project store and bus survive the page, so a single SIDEBAR::remove event invokes both handlers and sends two identical IPC requests.

Make sidebar listener registration idempotent, return a cleanup function, and unsubscribe when the editor page unmounts or the project store is disposed. Ignore repeated shortcut keydowns. The main-process confirmation flow remains unchanged; no concurrent-request deduplication is needed.

Type of change

• Bug fix (non-breaking, fixes an issue)
• New feature (non-breaking, adds functionality)
• Breaking change (causes existing functionality to change)
• Documentation update

Test plan

• Reproduced on macOS in Electron E2E: remount the editor page, select a sidebar file, press Delete once. With the original unguarded main-process implementation, the regression test received 2 dialogs instead of 1. The unit regression independently received 2 IPC calls for one bus event.
• Verified the lifecycle fix with main-process deduplication temporarily removed: the same E2E receives 1 dialog. Removed the earlier concurrent-request protection.
• 17 unit tests passed covering registration, unmount cleanup, store disposal, shortcut eligibility, confirmation, cancel, and retry.
• All 3 sidebar-delete Electron E2E tests passed; the remount test checks a single Delete keydown and a single dialog.
• pnpm run lint (0 errors; existing warnings), pnpm run typecheck, and pnpm run build:unpack.
• Screenshots/recording attached (not provided; dialogs/trash are stubbed in E2E to avoid deleting user files).

By submitting this pull request, I confirm that my contribution is made under the terms of the MIT license.