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/app/settings/push-actions.ts

@@ -0,0 +1,50 @@
+"use server";
+
+import { and, eq } from "drizzle-orm";
+import { db } from "@/lib/db";
+import { pushSubscriptions } from "@/modules/_core/schema";
+import { getCurrentSession } from "@/lib/session";
+import { sendPush } from "@/modules/_core/push";
+
+type PushSubscriptionJSON = {
+  endpoint: string;
+  keys: { p256dh: string; auth: string };
+};
+
+export async function subscribeToPush(
+  sub: PushSubscriptionJSON,
+  userAgent: string,
+): Promise<void> {
+  const { user } = await getCurrentSession();
+  await db
+    .insert(pushSubscriptions)
+    .values({
+      userId: user.id,
+      endpoint: sub.endpoint,
+      p256dh: sub.keys.p256dh,
+      auth: sub.keys.auth,
+      userAgent: userAgent.slice(0, 512),
+    })
+    .onConflictDoUpdate({
+      target: pushSubscriptions.endpoint,
+      set: { p256dh: sub.keys.p256dh, auth: sub.keys.auth },
+    });
+}
+
+export async function unsubscribeFromPush(endpoint: string): Promise<void> {
+  const { user } = await getCurrentSession();
+  await db
+    .delete(pushSubscriptions)
+    .where(
+      and(eq(pushSubscriptions.userId, user.id), eq(pushSubscriptions.endpoint, endpoint)),
+    );
+}
+
+export async function sendTestNotification(): Promise<void> {
+  const { user } = await getCurrentSession();
+  await sendPush(user.id, {
+    title: "famapp test",
+    body: "Push notifications are working!",
+    url: "/settings",
+  });
+}