## 1. Schema & Queries

- [ ] 1.1 Add idempotent `ALTER TABLE tags ADD COLUMN IF NOT EXISTS sms_enabled BOOLEAN NOT NULL DEFAULT TRUE;` to `db/schema.sql`; run `make db-up` (migrates existing DB)
- [ ] 1.2 Add sqlc queries in `internal/db/queries.sql`: `InsertScan` (tag_id, lat/lng nullable, location_shared, scanner_phone nullable), `GetLastAlertByTag` (latest scan with alert_sent=true), `UpdateTagDetails` extended with `sms_enabled`; `make generate`
- [ ] 1.3 New `internal/sms` package: `Sender` interface, `sms.NormalizeAU`, `sms.HaversineMeters`; `smslog` sender; `smsglobal` HTTP client (REST, key+secret, JSON; field names confirmed with MXT docs)

## 2. Scan Handlers

- [ ] 2.1 `internal/handlers/scan.go`: `POST /t/{tag_code}/scan` — parse optional lat/lng, record scan, apply 250 m / 10-min throttle, send SMS per rules, set `alert_sent`
- [ ] 2.2 `POST /t/{tag_code}/contact` — validate finder number, store on latest scan, SMS the owner with the finder's number
- [ ] 2.3 Wire `internal/sms` sender into `App` (log sender when `SMS_API_KEY` unset) + register routes in `main.go`

## 3. Public Page JS & Templates

- [ ] 3.1 `tag-public.html`: geolocation script (prompt on load, POST scan with coords, re-check button shown until shared, hidden after), `sms:` link with prefilled body, finder contact form + inline error
- [ ] 3.2 Branding sweep: "WhereWoof" → "Where Woof" in all templates + README; `<title>` → "Where Woof !"

## 4. Tag Management

- [ ] 4.1 `tag-edit.html` + `tags.go` edit handler: `sms_enabled` checkbox (default checked), saved via `UpdateTagDetails`

## 5. Verification

- [ ] 5.1 Extend the HTTP suite (`/tmp/verify.sh`): scan with location → scan row + alert logged + `alert_sent=true`; same-location re-scan in window → no second alert; >250 m re-scan in window → second alert; after 10 min → alert; `sms_enabled=false` → no alert; finder contact → stored + owner alert; `sms:` link and re-check button present; branding strings present
- [ ] 5.2 Unit test haversine (known distances) + NormalizeAU cases
- [ ] 5.3 Manual real-SMS check to `+61432374487` (real credentials, then removed)
- [ ] 5.4 `openspec validate scan-flow`; commit