## ADDED Requirements

### Requirement: Owner alert on scan
When a scan of an `sms_enabled` tag is recorded, the system SHALL send an SMS to the tag owner. The message SHALL include the item type and name, the scan time, a maps link when a location was shared, and the tag page link.

#### Scenario: Alert with location
- **WHEN** a scan with coordinates is recorded on an enabled tag outside the throttle window
- **THEN** the owner receives an SMS with item type, name, time, maps link, and tag page link, and `alert_sent = true` is recorded

#### Scenario: Alert without location (first scan)
- **WHEN** a scan without coordinates is recorded on an enabled tag outside the throttle window
- **THEN** the owner receives an SMS noting the finder did not share a location

### Requirement: sms_enabled disabled means no alerts
When a tag has `sms_enabled = false`, scans SHALL be recorded but no SMS SHALL be sent and `alert_sent` SHALL remain false.

#### Scenario: Informational tag scanned
- **WHEN** a scan is recorded on a tag with `sms_enabled = false`
- **THEN** no SMS is sent and `alert_sent = false`

### Requirement: Location-aware throttle
Within a 10-minute window since the last alerted scan of the same tag, the system SHALL send a new alert only if the new scan has a location more than 250 meters from the last alerted location. A scan at the same location SHALL be recorded without a new alert.

#### Scenario: Same location within window
- **WHEN** a second scan of the same tag arrives within 10 minutes at the same location
- **THEN** the scan is recorded and no SMS is sent

#### Scenario: Moved more than 250 m within window
- **WHEN** a second scan of the same tag arrives within 10 minutes more than 250 m from the last alerted location
- **THEN** a new SMS is sent

#### Scenario: After the window
- **WHEN** a scan arrives more than 10 minutes after the last alert for the tag
- **THEN** an SMS is sent regardless of distance

### Requirement: Swappable SMS sender
SMS sending SHALL go through an abstraction so that automated tests and development never send real SMS. With no SMS credentials configured, the app SHALL use a logging sender.

#### Scenario: No credentials in dev
- **WHEN** SMS credentials are not configured
- **THEN** sending an alert logs the message instead of calling the provider

### Requirement: International number format
Phone numbers SHALL be normalised to international format without a leading `+` or leading zero before sending (e.g. `+61423274487` or `0432374487` → `61423274487`).

#### Scenario: Number normalisation
- **WHEN** an owner or finder number is stored in any local format
- **THEN** the SMS provider receives the normalised international form