Feature: Recurring Tasks + Smart Reminders (NLP quick-add & Expo push)

**Summary**
Let users set **recurring tasks** (daily/weekly/monthly/custom RRULE) with **smart reminders** and **NLP quick-add**. Deliver **Expo push notifications** with actions (Complete / Snooze), sync via Supabase, and respect user **time zones**.

**Why**

* Core task app need: habits, bills, routines.
* Reduces churn: timely nudges → completion.
* “Type what you think” quick-add is a delight on mobile.

---

## Scope (MVP)

**UX**

* Quick-add understands:

* `pay rent every month on the 1st at 9am remind 1d`
* `water plants every sat 10am`, `review PRs daily 5pm remind 15m`
(Use `chrono-node` for parsing date/time; simple keywords for repeats/reminders.)
* Task editor: Recurrence (None/Daily/Weekly/Monthly/Custom), Time zone, Reminder offsets (e.g., 1d, 1h, 15m).
* Push notification with actions: **Complete**, **Snooze 1h** (deep links to the task).
* One-off reminders for non-recurring tasks supported with same UI.

**Data (Supabase)**

```sql
-- store Expo push tokens
create table if not exists public.user_devices (
id uuid primary key default gen_random_uuid(),
user_id uuid not null references auth.users(id) on delete cascade,
expo_push_token text not null unique,
platform text check (platform in ('ios','android','web')) default 'ios',
created_at timestamptz not null default now()
);

-- extend tasks
alter table public.tasks
add column if not exists recurrence_rrule text, -- e.g., FREQ=MONTHLY;BYMONTHDAY=1;BYHOUR=9;BYMINUTE=0
add column if not exists tz text not null default 'UTC', -- IANA tz
add column if not exists reminder_offsets_min int[] not null default '{30}', -- minutes before due
add column if not exists snoozed_until timestamptz; -- nullable
```

**RLS**

```sql
alter table public.user_devices enable row level security;
create policy device_owner
on public.user_devices for all
using (auth.uid() = user_id) with check (auth.uid() = user_id);
-- tasks table already owner-scoped; ensure same pattern for new columns
```

**Server (Supabase Edge Functions + Scheduler)**

* `register-device`: upsert `expo_push_token` for current user.
* `dispatch-reminders` (runs every minute via Supabase Scheduler):

1. Find tasks where any `due_date - offset` ∈ now()..now()+1m, considering `tz` and `snoozed_until`.
2. Send push via Expo API to all `user_devices` for that user.
3. Include actions payload `{action:'complete'|'snooze', taskId}`.
* `notification-action` (HTTP): handles action callback updates (complete task / set `snoozed_until = now()+interval '1 hour'`).

**Client (React Native / Expo)**

* On first launch (and Settings): request notifications permission, get Expo push token, call `register-device`.
* Quick-add input: try parser → build `recurrence_rrule`, `due_date`, `reminder_offsets_min`. Fallback to structured form.
* Deep link handling: navigate to task; apply action if present.
* Stats screen should reflect completions triggered from notifications in real-time.

---

## Acceptance Criteria

* User can create a recurring task with reminders via quick-add or editor.
* Devices receive a push at each reminder time; tapping **Complete** marks the task done; **Snooze 1h** sets `snoozed_until` and reschedules.
* Time zones honored; changing `tz` updates next occurrence correctly.
* Non-recurring tasks can have single reminders.
* Tokens are stored per device; removing app revokes token on next failed send.
* All operations respect RLS (no cross-user leakage).

---

## Implementation Notes

* **RRULE**: use `rrule` JS lib to compute `next_due_at` client-side; persist canonical RRULE in `recurrence_rrule`.
* **Parsing**: `chrono-node` for date/time; simple regex for `every|daily|weekly|monthly` and `remind `.
* **Expo**: `expo-notifications` for token + handling responses; on Android, add notification categories for actions.
* **Scheduler**: Supabase Scheduled Functions cron `* * * * *` to call `dispatch-reminders`. Batch sends.

---

## Tasks

* [ ] DB migrations (new columns + `user_devices` + RLS).
* [ ] Edge functions: `register-device`, `dispatch-reminders`, `notification-action`.
* [ ] Client: permissions, token register, deep links, actions handler.
* [ ] Quick-add parser + editor UI for recurrence/reminders/tz.
* [ ] Tests: RRULE next-occurrence calc, reminder windows, RLS, action flows.
* [ ] Docs: README section + short GIF, env vars for Expo/Supabase functions.