## ADDED Requirements

### Requirement: Finder contact form
The active tag page SHALL provide an input for the finder to leave their mobile number. Submitting SHALL store the number on the latest scan (`scans.scanner_phone`) and notify the owner by SMS with the finder's number.

#### Scenario: Finder leaves a number
- **WHEN** the finder submits a valid mobile number
- **THEN** the number is stored in `scans.scanner_phone` and the owner receives an SMS containing it

#### Scenario: Invalid input
- **WHEN** the finder submits an empty or malformed number
- **THEN** an inline error is shown and nothing is stored
