GMI Cloud's /v1/models returns only bare {id} rows, so dynamic discovery
resolved every model except the single bundled DeepSeek-V4-Flash seed with
a null context window, zero pricing, and no reasoning/thinking config.
Give the gmi-cloud mapper the same cross-provider canonical fallback that
SiliconFlow uses for the identical open-weight models: recover context
window, output limit, reasoning, and thinking ladder from the bundled
reference index while never borrowing another provider's pricing.
Fixes#8890
roboomp
8fc4555914