refactor(desktop): remove consumer-less IPC bridge surface

[Astro-Han]

Summary

Audit follow-up: remove IPC bridge surface with zero consumers in the renderer/overlay/e2e. All three items are safe deletions verified against current main (HEAD d20c9fc).

Findings

1. window:openSettings push has no sender since #390

• apps/desktop/src/preload/preload.ts:1017-1018 still exposes appWindow.subscribeOpenSettings; apps/desktop/src/renderer/app-shell-effects.ts:326 subscribes (unsubscribed at :336).
• The only sender (app-menu item 设置… / CommandOrControl+, in main-window.ts) was deleted in chore(ui): track Storybook-driven UI polish after file-boundary governance #390 (git show 5d696e463). No sender exists anywhere in main/ or the built dist/main.
• ⌘, is already handled by the renderer keydown handler (app-shell-effects.ts:279-281), so no functional loss.

2. dailyReview.list/get/delete duplicate the live *Archive variants

• preload/preload.ts:968-984: list/listArchives → same daily-review:list channel; get/getArchive and delete/deleteArchive likewise.
• Renderer only calls listArchives/getArchive (apps/desktop/src/renderer/app-shell-daily-review-bridge.ts:18,23). delete has no consumer in either spelling — the whole daily-review:delete channel is renderer-dead (archive-store retention cleanup calls store.deleteArchive directly).

3. cursor-subscription:logout is not gated by the experimental flag

• apps/desktop/src/main/subscription-ipc-main.ts:408-411 registers cursor-subscription:logout unconditionally, unlike the other 7 cursor-subscription:* channels gated by MAKA_CURSOR_SUBSCRIPTION_EXPERIMENTAL !== '0' (oauth/cursor-subscription-helpers.ts:79-80).

Proposed fix

• Delete subscribeOpenSettings from preload + the subscribeOpenSettings/handleOpenSettings wiring in app-shell-effects.ts (keep the keydown handler).
• Delete dailyReview.list/get/delete aliases from preload (and bridge-contract.d.ts if listed); optionally remove the daily-review:delete channel end-to-end.
• Gate cursor-subscription:logout with the same experimental flag, or remove it with the rest of the cursor surface (see the decision issue for the cursor subscription surface).

Owner

main process / preload (IPC boundary).

Acceptance

• Preload + renderer typecheck clean.
• ⌘/Ctrl+, still opens settings (keydown path).
• Daily Review archive journey unaffected.