feat(desktop): reminders notifications, snooze, overlay, and inbox view mode

[wpfleger96]

Builds four reminder features on the desktop app, all riding a single shared react-query spine. Reminders also move out of a standalone route and into the inbox as a view mode.

Phase 0 — useRemindersQuery spine

A single query keyed by ["reminders", pubkey] wraps fetchReminders. useReminderMutations wraps create/snooze/complete/cancel and invalidates the shared key on every success, so the badge, channel overlay, panel, and fire-on-due detection all read one source and can never disagree. This also auto-resolves the prior Phase 3 staleness where onUpdate() did not propagate outside the panel.

Phase 1 — Watermark fire-on-due + notification + badge

useReminderNotifications (mounted once in AppShell) detects due reminders with a persisted single-timestamp watermark in localStorage (buzz:lastReminderCheck:<pubkey>). On launch and every 30s it fires reminders where notBefore > watermark AND notBefore <= now AND status === "pending", coalesces multiple into one toast, then advances the watermark. The watermark seeds to now on first launch so history is not replayed; a reminder already past at the seed fails the strict > and surfaces only in the panel + badge, never as a toast. The OS toast respects desktopEnabled + the needs_action alert slot, with sound + dock bounce. The pure detection predicates (isDue, countDue, dueSince, groupReminders) live in lib/reminderFilters.ts so the highest-risk logic is unit-testable without react-query.

Phase 2 — Slack-style snooze dropdown

The hardcoded "snooze 1 hour" button becomes a Clock-icon dropdown (SnoozeMenu) over a shared lib/timePresets.ts module (TIME_PRESETS), the single source of truth for both the create dialog and snooze. "Custom…" reuses the native date/time input; a shared parseCustomDateTime future-time validator rejects notBefore <= now on both surfaces.

Phase 3 — Channel blue-tint overlay

RemindMeLaterProvider derives a Set of active (pending) reminder event IDs from the Phase 0 query and exposes it via context. MessageRow applies bg-blue-500/10 when a message's id is in the set; invalidation re-renders with a fresh set, so no stale tint.

Phase 4 — Reminders relocated into the inbox

Reminders is now a ?view=reminders mode inside the inbox, not a standalone nav item or route.

• The inbox list-pane header gains a Messages | Reminders view-mode toggle. Reminders mode renders RemindersPanel rows directly (pending + completed via groupReminders(reminders, includeDone), snooze/complete/cancel inline) and never enters the FeedItem selection model — it does not touch selectedItemId or InboxDetailPane. This dissolves the detail-pane/selection collision by construction.
• The auto-select effect and ?item= consume/mirror are gated to Messages mode. View-mode persists in the URL via ?view=reminders — validateHomeSearch is extended to allowlist view so the param survives navigation, reload, and the redirect target.
• deriveShellRoute stays pathname-only; /?view=reminders keeps selectedView === "home", accepted intentionally for the notification gate. No "reminders" arm is added to the union.
• /reminders is replaced by a redirect to /?view=reminders (TanStack throw redirect), preserving back/forward history and bookmarks. routeTree.gen.ts is unchanged (the redirect keeps the route registered). The Bell sidebar item, goReminders, and RemindersScreen are removed.
• The reminder badge has a single render site: the inbox Reminders toggle only. Count is due/overdue pending from the Phase 0 query, not folded into homeBadgeCount.

[wpfleger96]

Reminders v6 — UI screenshots

Visual walkthrough of the four UI changes in this PR, captured via the v6 Playwright screenshot spec (reminders-v6-screenshots.spec.ts).

Snooze dropdown

Snooze menu open on a fired reminder, showing the defer-time presets (In 30m / 1h / 3h / Tomorrow 9am / Next Mon 9am / Custom).

Blue-tint overlay

The bg-blue-500/10 tint applied to a message row with an active reminder, visibly distinct from untinted rows.

Inbox Reminders view

The inbox Reminders view — the v6 relocation target after the sidebar nav teardown — grouping reminders into OVERDUE and TODAY, each row with done / snooze / dismiss actions.

Reminder surfacing as due

The reminder surfacing as due — the watermark-guarded fire path fixed in this PR. The actual fire-on-due notification is an OS-native Notification (mocked in the harness), so the captured surface is the closest in-app evidence: the Reminders badge incrementing and the overdue row appearing the moment the reminder comes due.

[wpfleger96]

Reminders desktop — slider→dropdown rework (shots after Will's correction)

Reminders is now the 6th entry in the existing inbox filter dropdown (All / Mentions / Needs Action / Activity / Agents / Reminders), not a pill-slider. Selecting it swaps the list body to the reminders view; the Complete/Snooze/Cancel row actions are fully preserved. Captured at tip 14ce20cd, rebased clean on current main.

Filter dropdown — Reminders option

The existing inbox filter dropdown now carries a 6th Reminders entry alongside the five message filters, with its distinct due-reminder badge on the dropdown affordance.

Message row action — Remind me later

The per-message action menu exposes Remind me later, the entry point for scheduling a reminder off any message.

Remind-me-later dialog

Selecting Remind me later opens the time-picker dialog for choosing when the reminder fires.

Reminders view — empty

With the Reminders filter selected and no reminders scheduled, the body renders the empty reminders view.

Reminders view — active

Scheduled reminders render grouped (e.g. a TODAY group) with Complete / Snooze / Cancel row actions intact on each.

Reminders view — fired / overdue

Fired and overdue reminders surface in the reminders view, row actions preserved.