Add current_period tracking to subscriptions, document prediction engine, and refactor station list UI

Add current_period_start, current_period_end, and stripe_data columns to subscriptions table via migration. Extend Subscription model with datetime casts for new fields. Create comprehensive prediction engine documentation covering signals, aggregation, confidence calibration, and weekly summary logic. Add PredictionFull Vue component displaying action label, reasoning, and 7-day context. Refactor StationList to collapse outdated stations behind expandable section. Add UpsellBanner component with station count formatting. Create .claude/settings.json denying .env file access. Add todo.md tracking Stripe dashboard setup, production deployment steps, and E2E QA checklist. Update .env.example with fuel-finder credentials, Anthropic config, and complete Stripe price IDs.

todo.md

@@ -0,0 +1,54 @@
+# Todo
+
+Working checklist. Add sections per area. Tick boxes as you go.
+
+---
+
+## Stripe
+
+Spec: `docs/superpowers/specs/2026-04-23-stripe-subscription-lifecycle-design.md`
+Rules: `.claude/rules/payments.md`
+
+### Pre-production (test mode first, then repeat in live mode)
+
+- [ ] **Stripe Dashboard — retry schedule.** Billing → Automations → Subscription retry rules. Switch Smart Retries → Custom. Retry on days 1, 3, 5. After final retry → *Cancel subscription*.
+- [ ] **Stripe Dashboard — customer emails.** Emails → Customer emails. Enable "Successful payments", "Failed payments", "Upcoming renewals".
+- [ ] **Stripe Dashboard — branding.** Settings → Branding. Upload FuelAlert logo, set primary colour to match app accent.
+- [ ] **Stripe Dashboard — Customer Portal.** Settings → Billing → Customer Portal. Allow plan changes across all 6 prices (basic/plus/pro × monthly/annual), cancellation at period end only, card updates, invoice history. Hide everything else.
+- [ ] **Stripe Dashboard — webhook endpoint.** Developers → Webhooks. Add endpoint at `{APP_URL}/stripe/webhook`. Subscribe to: `customer.subscription.created`, `customer.subscription.updated`, `customer.subscription.deleted`, `invoice.payment_succeeded`, `invoice.payment_failed`. Copy signing secret → production `.env` as `STRIPE_WEBHOOK_SECRET`.
+
+### Production env + server
+
+- [ ] **`.env` keys** set on production:
+  - `STRIPE_KEY=pk_live_...`
+  - `STRIPE_SECRET=sk_live_...`
+  - `STRIPE_WEBHOOK_SECRET=whsec_...`
+  - `CASHIER_CURRENCY=gbp`
+  - `QUEUE_CONNECTION=redis`
+  - `STRIPE_PRICE_BASIC_MONTHLY`, `STRIPE_PRICE_BASIC_ANNUAL`
+  - `STRIPE_PRICE_PLUS_MONTHLY`, `STRIPE_PRICE_PLUS_ANNUAL`
+  - `STRIPE_PRICE_PRO_MONTHLY`, `STRIPE_PRICE_PRO_ANNUAL`
+- [ ] **Run `php artisan migrate`** — adds `users.grace_period_until`.
+- [ ] **Queue worker** consuming both queues: `--queue=notifications,default` (reminders go on the `notifications` queue).
+- [ ] **Redis persistence** (AOF or RDB) enabled — delayed jobs sit for 3–5 days.
+- [ ] `php artisan route:list --name=billing` — confirm 4 routes (checkout, portal, success, cancel).
+
+### E2E QA (Stripe test mode)
+
+Requires the Dashboard + env tasks above done first. Stripe test cards:
+
+- `4242 4242 4242 4242` — success
+- `4000 0000 0000 0341` — renewal fails (use to test dunning)
+
+- [ ] Sign up on each paid tier × both cadences (6 combos) → confirm tier shows.
+- [ ] Upgrade basic → pro via Portal → confirm instant swap.
+- [ ] Downgrade pro → basic via Portal → confirm change scheduled for period end.
+- [ ] Cancel mid-period → features persist until period end → drop to free.
+- [ ] Use `4000 0000 0000 0341` + `stripe trigger invoice.payment_failed`:
+  - Banner appears on dashboard with correct "by {date}" string.
+  - Day-3 job is queued (visible via `php artisan queue:listen notifications`).
+  - Day-5 job is queued.
+  - Final Stripe retry fails → `customer.subscription.deleted` → user drops to free, WhatsApp + SMS prefs disabled, banner disappears.
+- [ ] Recover mid-grace (update card via Portal) → `invoice.payment_succeeded` clears grace, banner disappears, queued reminders silently no-op when they run.
+
+---