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/_core/notify.ts

@@ -0,0 +1,52 @@
+import { eq } from "drizzle-orm";
+import { db } from "@/lib/db";
+import { notifications, users } from "./schema";
+import { sendPush } from "./push";
+
+type NotifyPayload = {
+  title: string;
+  body: string;
+  url?: string;
+  channels?: ("push" | "inapp" | "ntfy")[];
+};
+
+export async function notify(userId: string, payload: NotifyPayload) {
+  const channels = payload.channels ?? ["push", "inapp"];
+
+  const [user] = await db
+    .select({ notifPush: users.notifPush, notifInApp: users.notifInApp, notifNtfy: users.notifNtfy })
+    .from(users)
+    .where(eq(users.id, userId))
+    .limit(1);
+
+  if (!user) return;
+
+  const pushEnabled = process.env["VAPID_PUBLIC_KEY"] && process.env["VAPID_PRIVATE_KEY"];
+
+  if (channels.includes("push") && user.notifPush && pushEnabled) {
+    await sendPush(userId, payload).catch((err) =>
+      console.error("[famapp] push channel failed:", err),
+    );
+  }
+
+  if (channels.includes("inapp") && user.notifInApp) {
+    await db.insert(notifications).values({
+      userId,
+      title: payload.title,
+      body: payload.body,
+      url: payload.url,
+    });
+  }
+
+  if (channels.includes("ntfy") && user.notifNtfy) {
+    const ntfyUrl = process.env["NTFY_URL"];
+    const ntfyTopic = process.env["NTFY_TOPIC"];
+    if (ntfyUrl && ntfyTopic) {
+      await fetch(`${ntfyUrl}/${ntfyTopic}`, {
+        method: "POST",
+        headers: { Title: payload.title, "Content-Type": "text/plain" },
+        body: payload.body,
+      }).catch((err) => console.error("[famapp] ntfy delivery failed:", err));
+    }
+  }
+}