Build a Parking Reservation API

Problem/Feature Description

A parking garage needs a backend API to manage parking spot reservations. Build it in Go using the standard library.

Resources:

• ParkingSpot: { id, level, number, type (regular/handicap/ev), isAvailable }
• Reservation: { id, spotId, licensePlate, startTime, endTime, createdAt }

Endpoints:

• GET /api/spots -- list all spots, with optional ?type=ev&available=true filters
• GET /api/spots/{id} -- get a single spot
• POST /api/spots -- create a spot (level and number required; combination must be unique)
• POST /api/reservations -- create a reservation:
  • spotId, licensePlate, startTime, and endTime are required
  • spot must exist and be available
  • endTime must be after startTime
  • startTime must not be in the past
  • mark the spot as unavailable
• GET /api/reservations/{id} -- get a reservation
• DELETE /api/reservations/{id} -- cancel a reservation (mark the spot as available again)

Seed with 10 parking spots across 2 levels. Use in-memory storage.

Output Specification

Produce:

• main.go -- entry point and server setup
• Source files for handlers, models, errors, and any middleware
• go.mod

You may organize files as you see fit.