Implement tasks 40, 41, 42: web push, notification bus, reminders engine

Task 40 — Web Push (VAPID):
- Add web-push package + @types/web-push
- pnpm vapid:generate script prints VAPID_PUBLIC_KEY, VAPID_PRIVATE_KEY, NEXT_PUBLIC_VAPID_PUBLIC_KEY
- push_subscriptions schema + migration 0013
- _core/push.ts: sendPush() iterates subscriptions, prunes 404/410 stale entries
- SW push/notificationclick event handlers added to generated sw.js template
- PushOptIn client component on /settings (opt-in, disable, send test)

Task 42 — Notification bus + ntfy adapter:
- notifications table + notif_push/notif_inapp/notif_ntfy user columns (migration 0013)
- _core/notify.ts: notify() fans out to push, in-app DB, and optional ntfy POST
- NotificationBell server component in AppNav: unread badge, dropdown inbox, mark-read
- NotifyChannelToggles client component in /settings

Task 41 — Reminders engine:
- fired_at + created_by added to reminders; default channel changed to 'auto'
- _core/reminders.ts: scheduleReminder (upsert), cancelReminder, listReminders, tickReminders
- tickReminders uses pg_try_advisory_xact_lock for horizontal-scale safety
- src/instrumentation.ts starts reminder worker (30s tick) on Node.js boot
- Notes actions use scheduleReminder/cancelReminder instead of raw SQL
- Calendar createEvent: optional remindMinutesBefore, deleteEvent: cancelReminder
- Calendar-shell: "Remind me 30 min before" checkbox on new event form

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/modules/calendar/components/calendar-shell.tsx

@@ -40,6 +40,7 @@ type EventDraft = {
   allDay: boolean;
   location: string;
   notes: string;
+  remindMinutesBefore: number | null;
 };
 
 const DEFAULT_COLOR = "#2563eb";
@@ -92,6 +93,7 @@ export function CalendarShell({
       allDay,
       location: "",
       notes: "",
+      remindMinutesBefore: 30,
     });
   }
 
@@ -107,6 +109,7 @@ export function CalendarShell({
       allDay: row.allDay,
       location: row.location ?? "",
       notes: row.notes ?? "",
+      remindMinutesBefore: null,
     });
   }
 
@@ -148,7 +151,10 @@ export function CalendarShell({
           ),
         );
       } else {
-        const created = await createEvent(payload);
+        const created = await createEvent({
+          ...payload,
+          remindMinutesBefore: selectedEvent.remindMinutesBefore,
+        });
         setLastCalendarId(payload.calendarId);
         setEventRows((current) => [...current, created]);
       }
@@ -489,6 +495,22 @@ export function CalendarShell({
                   setSelectedEvent({ ...selectedEvent, notes: event.target.value })
                 }
               />
+              {!selectedEvent.id && (
+                <label className="flex items-center gap-2 text-sm">
+                  <input
+                    type="checkbox"
+                    className="size-4 cursor-pointer"
+                    checked={selectedEvent.remindMinutesBefore !== null}
+                    onChange={(e) =>
+                      setSelectedEvent({
+                        ...selectedEvent,
+                        remindMinutesBefore: e.target.checked ? 30 : null,
+                      })
+                    }
+                  />
+                  Remind me 30 min before
+                </label>
+              )}
               <div className="flex items-center justify-between gap-2 pt-2">
                 <div className="flex gap-2">
                   {selectedEvent.id && (