Grok Build previously reused the whole Codex preset list, leaking
cn_official providers and Codex default models into the Grok CLI form.
Replace the inline filter with a standalone, independently maintained
preset module (no data linkage to codexProviderPresets):
- drop cn_official direct providers and open-source-only hosts
(SiliconFlow/ModelScope/Novita/Nvidia/AtlasCloud/OpenCode Go) that
have no Grok models upstream
- keep aggregators and third-party relays with grok-4.5 as the default
model (x-ai/grok-4.5 for OpenRouter-style namespaced routers)
- move the Grok Official seed entry into the presets module
- add standalone integrity tests; retarget the form's chat-mapping test
since no openai_chat preset remains in the list