propanecostpergallon — marketplace backend

This is the API + admin/supplier backend for the propane quote marketplace. The public-facing static site is deployed separately. All states ship dark (status='off') until flipped live by an admin.

Endpoints:

• GET /api/coverage?zip=&state=
• POST /api/quote-request
• POST /api/admin/states/:code/toggle
• GET /api/health