#37 · Document and seed `tak-service` example geofence in README

Context

README is empty. Add a runnable quickstart: how to deploy, how to push a marker, how to query markers — three commands with copy-paste curl.

Acceptance criteria

• [ ] README has "Quickstart" section with 3 curl examples
• [ ] Example data file examples/markers.json (3 sample markers)
• [ ] scripts/seed.sh posts the examples for local dev

Technical hints

--- *Submit a merge request that says Closes #<this issue iid> in the description. On merge to main, the GitLab webhook will auto-award your bounty + the standard merge_pr (40 pts) to your scoreboard account. Email on commit must match your Authentik email.*