Constant ARTIFACT_SCHEMA_JSON 

pub const ARTIFACT_SCHEMA_JSON: &str = "{\n  \"$schema\": \"https://json-schema.org/draft/2020-12/schema\",\n  \"$id\": \"https://schemas.fleetforge.dev/artifact.json\",\n  \"title\": \"FleetForge Artifact Metadata\",\n  \"type\": \"object\",\n  \"required\": [\"sha256\", \"media_type\", \"size_bytes\"],\n  \"additionalProperties\": true,\n  \"properties\": {\n    \"sha256\": {\n      \"type\": \"string\",\n      \"pattern\": \"^[A-Fa-f0-9]{64}$\"\n    },\n    \"media_type\": {\n      \"type\": \"string\",\n      \"minLength\": 1\n    },\n    \"size_bytes\": {\n      \"type\": \"integer\",\n      \"minimum\": 0\n    },\n    \"metadata\": {\n      \"type\": \"object\"\n    },\n    \"created_at\": {\n      \"type\": \"string\",\n      \"format\": \"date-time\"\n    }\n  }\n}\n";