Phase 7: notify and send via Apprise (Email + WhatsApp)

The morning briefs go out through the house Apprise API on `.35:8210`: one
brief per boy and one combined brief to Jo and Sam (FR-9, FR-14). The service
names an Apprise tag (`harry_email`, `joanna_whatsapp`, ...) and never holds an
address, a phone number or an SMTP password (AGENTS.md §10 rule 3).

- internal/apprise: keyed and stateless client, tag filtering, and error
  redaction so nothing sensitive reaches a log, a row or a screen.
- internal/brief: builds the per-boy and the combined brief, delivers on email
  and WhatsApp, records every attempt in `notifications` (migration 004 adds
  scope, channel, tag, ok and error) and fails loudly.
- Send panel (§5 screen 4): recipients, channels, an exact preview, Send now,
  plus the Send action on a stored draft (FR-10). The dashboard shows a
  Morning briefs banner and the Sends list.
- POST /notify/morning: the bearer-token endpoint the 6:00am n8n schedule
  calls. 207 when a channel or a scan failed; `dry_run=1` checks the wiring
  without messaging the family.
- scripts/morning-brief.sh: scan both children, then send. It is the n8n job;
  deploy/n8n-morning-brief.json is the ready-to-import workflow (06:00 daily).
- FR-12: a failed scan is never "nothing due" -- the brief says so, and the run
  exits non-zero. A failed delivery is recorded with no sent_at.
- The long no-due-date tail is capped in the sent brief so it stays brief
  (§10 rule 6); overdue work is never capped.

Verified live: 8 deliveries recorded (4 email, 4 WhatsApp) with HTTP 200 and
sent_at, and the endpoint answers 401/200/207 as documented. Evidence in
docs/phase-7-notify-notes.md.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

internal/store/migrations/004_notifications_send.sql

@@ -0,0 +1,20 @@
+-- Migration 004 — Phase 7 notify and send (AGENTS.md §4 FR-9/FR-13/FR-14,
+-- §11 Phase 7).
+--
+-- `notifications` becomes the delivery log: one row per brief per recipient per
+-- channel. The brief text is the `summary` column (it was already there), and
+-- the new columns record where the row belongs (scope), which channel and
+-- Apprise tag were used, whether the delivery succeeded, and the redacted error
+-- when it did not. A failed send is therefore visible and loud instead of being
+-- lost (FR-12).
+--
+-- A draft (built but not sent) is a row with an empty `channel`, ok = 0 and
+-- sent_at NULL, which is what the Phase 5 dashboard already showed.
+
+ALTER TABLE notifications ADD COLUMN scope   TEXT    NOT NULL DEFAULT '';
+ALTER TABLE notifications ADD COLUMN channel TEXT    NOT NULL DEFAULT '';
+ALTER TABLE notifications ADD COLUMN tag     TEXT    NOT NULL DEFAULT '';
+ALTER TABLE notifications ADD COLUMN ok      INTEGER NOT NULL DEFAULT 0;
+ALTER TABLE notifications ADD COLUMN error   TEXT    NOT NULL DEFAULT '';
+
+CREATE INDEX IF NOT EXISTS idx_notifications_scope ON notifications(scope, created_at);