{
  "type": "object",
  "required": [
    "schema_version",
    "profile_id",
    "display_name",
    "school_level",
    "session_count",
    "unlocked_regions",
    "skills",
    "rewards"
  ],
  "additionalProperties": false,
  "properties": {
    "schema_version": { "type": "integer", "minimum": 1 },
    "profile_id": { "type": "string", "pattern": "^[a-z][a-z0-9_]*$" },
    "display_name": { "type": "string", "minLength": 1 },
    "school_level": { "type": "string", "enum": ["CE1", "CE2"] },
    "session_count": { "type": "integer", "minimum": 0 },
    "unlocked_regions": { "type": "array", "items": { "type": "string" } },
    "skills": { "type": "object" },
    "rewards": {
      "type": "object",
      "required": ["stars", "items"],
      "additionalProperties": false,
      "properties": {
        "stars": { "type": "integer", "minimum": 0 },
        "items": { "type": "array", "items": { "type": "string" } }
      }
    }
  }
}