[sahilPadmani]

Adds Cerebras Inference as a yellow model vendor: vendor = "cerebras", Chat Completions at https://api.cerebras.ai/v1, key in CEREBRAS_API_KEY.

Fixes #4

What

• crates/vendors/yellow/src/cerebras.rs, following deepseek.rs as the issue suggests, in both ALL lists.
• Cerebras returns reasoning as reasoning, not DeepSeek's reasoning_content (reasoning guide, API reference), and takes it back in an assistant message as reasoning. With a straight copy, chat::read leaves delta.reasoning unread, so an Anthropic, Responses or Gemini client fails with untranslatable whenever the model reasons, and reasoning sent back in history goes as reasoning_content.
• So its dialect renames delta.reasoning to reasoning_content before the existing chat::read, and the reasoning_content that chat::reasoning_written writes to reasoning. This is in cerebras.rs alone, as groq.rs and gemini.rs handle their quirks; the kit and the other vendors are unchanged.
• Its top-level time_info needs nothing: openai-chat already treats it as inert.
• Docs: a row in docs/vendors.md under Yellow and its base URL there, the vendor lists in docs/configuration.md and the README, and its LobeHub logo in docs/assets/vendors/ and the UI's vendor-icons.ts.

Checks

• cargo fmt --all --check, cargo clippy --workspace --all-targets --all-features -- -D warnings: clean.
• cargo test --workspace --all-targets --all-features: 631 passed; cargo test --workspace --doc --all-features: passed. a_bad_provider_is_an_error now lists cerebras.
• apps/ui: pnpm lint, pnpm typecheck, pnpm test (196): pass.
• Through the built binary against a local fake that answers as Cerebras's docs describe: OpenAI Chat, Anthropic, Responses and Gemini clients, streamed and not, all get the reasoning and the answer, and Cerebras receives reasoning sent back as reasoning. With a straight copy of deepseek.rs, every client but OpenAI Chat fails with untranslatable. I can share the fake if useful.
• Against Cerebras's live API with a dummy key: /v1/chat/completions and /v1/messages both return Cerebras's own wrong_api_key, so the base URL, key header and routing are right. No live run with a real key.

[lihe07]

LGTM

[sahilPadmani]

The deny failure is RUSTSEC-2026-0383 (webpki-root-certs), published after main's last green run, so it also fails on main. It doesn't come from this change. cargo update -p webpki-root-certs -p rustls-webpki fixes it.

[lihe07]

The deny failure is RUSTSEC-2026-0383 (webpki-root-certs), published after main's last green run, so it also fails on main. It doesn't come from this change. cargo update -p webpki-root-certs -p rustls-webpki fixes it; happy to open a separate PR

sounds good. im merging this one first.