Remind about approvals waiting 15 min, switch each notification kind, one notification per chat

[Birfy]

Fixes #469 (first slice, owner decision 2026-10-20 option a). Builds on #353's notifications (#470). Quiet hours, mute and an in-app list stay for later; friends'/team notifications wait for #51.

What

• Waiting too long: an approval still waiting 15 min after it started (or after the window opened, if it started earlier) gets one more notification: Coder has waited 15 min for your approval. A client timer is set for the next due approval and cleared with the effect; a decided approval gets none.
• Per-kind switches: Settings → General → Notifications keeps the main switch and adds Waiting for approval (covers the reminder), Finished and Failed (prefs.notify, on unless false; disabled while the main switch is off). set-prefs takes notify: { approval | finished | failed: boolean }, keeps only the off ones.
• One per chat: every notification of a chat or group shares the tag ds-bot-<chat id>, so a newer one replaces the older, and the body counts the updates (3 updates) since the chat was last on screen or its notification clicked. Several events of one chat in one pass become one notification (the newest).
• Unchanged: never asks for permission, nothing from before the window opened, a click only opens the chat (no buttons, never approves or sends).

Test

• New tests in core/test/approval-notices.test.js (reminder timing and cleanup, reminder for pre-window approvals, per-kind switches, per-chat collapse and count reset, Settings rows) and install.test.js (set-prefs notify).
• ARCH_DOCS_BASE=origin/main TZ=UTC npm run verify: pass (core 1082, social 296, tree 80, timeline 83, scripts 93, interop 37, live-e2e 16; 0 failures). changelog.mjs check: ok.
• Not run: live Mac instances, real OS notifications in a desktop build.

Risk tier: T2 (estimate; the controller sets the label)

[Birfy]

Self-review: PASS
Tip SHA: 538a69a
Ran:

• ARCH_DOCS_BASE=origin/main TZ=UTC npm run verify (incl. core lint, plugin lint, build-client --check, ds-bot-patches check, arch-docs): pass, 0 failures (core 1082, social 296, tree 80, timeline 83, scripts 93, interop 37, live-e2e 16)
• node .github/scripts/changelog.mjs check: ok
• GH_REPO=ThinkFlowLab/FlyBot node .github/scripts/risk-gate.mjs --pr 492: T3 (path core/src/host/channel.js)
• CI at this tip: tests-ok, test, package, plugins (social/tree/timeline), risk tier, reviewed tip: all green
• Diff reviewed against the owner design rules: notifications carry no buttons and never approve, reject or send (approval only via explicit UI buttons, unchanged); only the user's own Bots (host filter from Proactive reminders 1/3: event reminders (approval waiting, failed, finished) in app and desktop #353 unchanged, no friend/team scope, waits for [Team] Gate cross-owner agent routes by per-Bot grants (default deny; superseded the publication gate) #51); English UI with zh entries; switches live in the existing Settings → General → Notifications card; scope limited to the Proactive reminders 1/3 follow-up: quiet hours, mute, waiting-too-long #469 owner decision (a): 15-min reminder, per-kind switches, per-chat collapse. No quiet hours, mute or in-app list.
  Not run:
• Live Mac instances; real OS notifications in a desktop build (Notification is faked in tests)

[Birfy]

Self-review: PASS
Tip SHA: 79e6a40
Ran:

• Merged origin/main (303c0d6, includes Fit chat approvals and the Agent inbox to a phone-width screen #481/Keep live shares in People with access using Bot Social's reply_only #501/Show a friend's first line and its approval card live: read friends' inboxes fast while a window is on screen #505) into feat/469-waiting-reminder-toggles; conflicts only in generated patches (regenerated) (2026-10-20 15:04 Asia/Shanghai).
• ARCH_DOCS_BASE=origin/main TZ=UTC npm run verify: passed (core lint + arch-docs OK, plugin lint OK, build-client --check OK, ds-bot-patches check OK; core/social/tree/timeline/scripts/interop/live-e2e all green).
  Not run:
• Live Mac instances or the production Bot Social server (not touched).

[Birfy]

Self-review: PASS
Tip SHA: 0600e07
Ran:

• ARCH_DOCS_BASE=origin/main TZ=UTC npm run verify (pass)
• reviewed diff at tip vs owner design rules
  Not run:
• live Mac instances / production Bot Social