SUP-002: Contact Us — support ticket submission form

## Overview
A contact form that lets users submit a support request. The submission creates a ticket in the support queue and sends an auto-acknowledgement email.

## Acceptance Criteria
- [ ] Contact form: name, email, order ID (optional), subject, message
- [ ] Submission creates a ticket record and returns a ticket ID
- [ ] Auto-acknowledgement email sent to the user (via NOTIF-001)
- [ ] Support team receives notification of new ticket
- [ ] Form is accessible without login; logged-in users have fields pre-filled

## Depends On
- #37 (AUTH-001 — pre-fill for logged-in users)
- #51 (NOTIF-001 — auto-acknowledgement email)

No files or tests are named. Start by reviewing dependent issues #37 (AUTH-001) and #51 (NOTIF-001), then locate the existing form, ticket, and notification entry points. Done means all listed acceptance criteria pass, including anonymous submission, logged-in prefill, ticket ID return, and both email notifications.

Written by the indexing model from the issue text.