MVP test

Test the API.

Generate three images, inspect the responses, and watch caching work.

GEN_TOKEN (if your instance requires it)

Cache hits are instant and free — generate the same prompt twice to see X-Cache: HIT.
Cache misses call Gemini and take ~2–10s.
GEN_TOKEN— if the server requires it and you don't supply it above, new generations return 401.
Moderation — blocked prompts return 400 before any Gemini call.