image-cache — give it a prompt, get an image

GET  /healthz
GET  /v1/image?prompt=&judge=1&generate=1&model=   image bytes + X-Cache-Status/Layer/Image-Id/Prompt-Key/Latency-Ms/Cost-USD
GET  /v1/image.json?prompt=…                        {cacheStatus, layer, imageId, promptKey, url, prompt, latencyMs, costUsd}
GET  /v1/images/<id>.jpg                            stored image (immutable, JPEG)
POST /api/query {text, auto_judge}                  candidates + decision (demo/introspection)
POST /api/generate {text, model}                    generate + cache
POST /api/judge {text, id}                          one judge verdict
GET  /api/stats · GET /api/examples