Add fuel API ingestion and historic storage design spec

Includes verified API authentication flow, correct base URL, all DB
table schemas for stations, current prices, history, and archive.
Fuel types corrected to match live API (B7_STANDARD, B7_PREMIUM).

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

.claude/rules/notifications.md

@@ -0,0 +1,68 @@
+# Notifications
+
+## Tier-to-channel mapping
+
+| Tier       | Price  | Email | Push (PWA) | WhatsApp | SMS       |
+|------------|--------|-------|------------|----------|-----------|
+| Free       | £0     | ✓ weekly digest | ✗ | ✗ | ✗ |
+| Basic      | £0.99  | ✓ daily | ✓ daily | ✓ daily | ✗ |
+| Plus       | £2.49  | ✓     | ✓         | ✓        | ✓ max 1/day triggered |
+| Pro        | £3.99  | ✓     | ✓         | ✓        | ✓ max 3/day triggered |
+
+## NotificationDispatchService
+
+Reads user tier via Cashier, returns allowed channels:
+```php
+public function channelsFor(User $user): array
+// Returns e.g. ['mail', 'vonage-whatsapp'] for Basic tier
+// Returns ['mail', 'vonage-whatsapp', 'vonage-sms'] for Plus+
+```
+
+Never fire SMS unless confidence ≥ 70 AND user is Plus/Pro.
+Never fire more than 1 notification per user per day unless they are Pro tier.
+Log every sent notification to `alerts` table.
+
+## Laravel Notification class
+
+One `FuelPriceAlert` notification class with `via()` returning channels based on tier.
+Subject line / message copy adapts based on `recommendation` and `confidence`.
+
+## WhatsApp (Vonage)
+
+- Provider: Vonage Messages API (WhatsApp channel)
+- PHP package: `vonage/client`
+- Template: utility category (one-way alert) — pre-approved template required by Meta
+- Opt-in: phone number + OTP flow (see otp_verifications table)
+- User must have `whatsapp_verified_at` set — never send to unverified numbers
+- Cost: ~0.3–0.5p per message (utility rate)
+- Message format: keep under 160 chars. Include station name, price, and recommendation reason.
+
+## SMS (Vonage — Plus/Pro only)
+
+- Same Vonage client, SMS channel
+- Triggered only (not daily) — fires when signal strength ≥ 2 AND price event warrants it
+- Plus: max 8 SMS/month (enforced via alerts table count)
+- Pro: max 30 SMS/month
+- Cost: ~3.5p per message UK
+
+## Email
+
+- Driver: Mailgun (configured in .env)
+- Free tier: weekly digest every Monday 8am
+- Basic+: daily summary if recommendation is not `no_signal`
+- Use Mailable classes, not raw Mail::send
+- Templates in `resources/views/emails/`
+
+## Push notifications (OneSignal)
+
+- Free plan: up to 10,000 subscribers
+- Player ID stored in `users.push_token`
+- Use OneSignal REST API — no official Laravel package needed, simple HTTP call
+- PWA service worker setup required (separate task)
+- Basic+: daily push alongside email
+
+## Queue
+
+All notifications are dispatched as queued jobs — never send synchronously.
+Use `FuelAlertNotificationJob` dispatched per user.
+Queue: `notifications` (separate from default queue for priority control).