Verified the direct_* providers end-to-end after billing was enabled.
- OpenAI direct_gpt-4o / direct_gpt-4o-mini: working.
- Gemini: gemini-2.0-flash 404s (LiteLLM 1.55.10 rewrites it to a retired
experimental name) and gemini-1.5-pro is retired -> switch to the current GA
gemini-2.5-flash / gemini-2.5-pro (both verified).
- Drop direct_o3-mini: o-series needs max_completion_tokens, which 1.55.10 won't
translate from the max_tokens clients (Open WebUI) send -> 400. Re-add after a
LiteLLM bump.
Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
