feat(providers): keep registered setup connection-only (#142202)

feat(providers): keep registered setup connection-only (#142202)

Registered provider setup now saves a connection without pinning a copy of the built-in model catalog. Add shared connection-only presets and move the Cloudflare AI Gateway, Featherless, Hugging Face, LongCat, Meta, Mistral, NVIDIA, Synthetic, Together, regular Xiaomi, and Z.AI registrations to them.

Ordinary setup preserves authored rows, defaults, fallbacks, and aliases. Explicit replace mode keeps the existing catalog-merge and required-default rules. Published helper APIs keep their catalog-seeding behavior. Shared descriptors remove duplicate provider decisions, and generated replace rows belong to the resulting config.

The new SDK imports require a paired host/plugin release. The existing version-sync and package builder update the plugin API and peer ranges with that release. This change does not claim compatibility between the new plugin imports and an older released host.

Validation:

- 128 focused SDK and provider checks pass. Four connection-only checks fail when the mode condition is deliberately removed; the correct source is restored.
- Real registered NVIDIA setup saves seven generated rows on the pinned baseline and zero on the candidate. Authored merge/replace settings and the available default remain intact.
- The required CI artifact passes compiled Mistral setup for fresh, authored merge, and authored replace configurations. A real Gateway lists the configured default and returns one synthetic provider reply with matching requested, effective, and response models. Catalog and inference leave saved configuration unchanged.
- Required CI passed on the exact candidate. Runtime proof uses its recorded CI merge build and matching compiled host/plugin, with existing dependencies and isolated synthetic state. No real vendor request or package publication occurred.
- Independent acceptance passed all five clauses for the retained NVIDIA/Mistral observations. It did not replay runtime or claim coverage beyond those representative scenarios.

The earlier fixture failure from comparing resolved configuration with raw saved JSON remains recorded. Its completed setup was preserved and was not repeated. The artifact's unrelated standalone GoogleChat dependency-link failure is also retained; the exercised Mistral dependency path completed successfully.

Co-authored-by: Ayaan Zaidi