Live tech tracking — public /track page (Uber-style)

When a tech taps "I'm on my way," your customer gets a public tracking link they can open on any phone — no login required. The page shows the tech's avatar, your org logo, a live map with the tech's pin moving, and a real-time ETA.

The customer flow:
1. Customer receives a text + email when the tech taps "On my way" — the message includes a /track/:token link
2. Open the link on any device — no app, no login
3. See the tech's avatar, org logo, ETA, and live map
4. ETA updates every 30 seconds based on the tech's position and traffic

Privacy:
• The tracking token is a bearer credential — anyone with the link can see the tech's position, but no one else
• Tracking stops automatically when the tech taps "I've arrived"
• The token expires 4 hours after the job is marked Completed (configurable)
• No PII about the tech beyond first name and avatar — no phone, no other jobs, no schedule

This is the same UX customers expect from Uber, Lyft, and DoorDash. Removing "where are they?" calls saves both the customer and dispatch real time on every job.