refactor(schema): separate provider and model settings - #49850

Summary

Split provider and model settings into distinct public contracts while preserving open-ended provider-package options.

type ProviderSettings = {
  timeout?: number | false
  chunkTimeout?: number
  compaction?: { type: "summary" } | { type: "native" }
  transport?: "http" | "websocket"
} & Record<string, any>

type ModelSettings = {
  compaction?: { type: "summary" } | { type: "native" }
} & Record<string, any>

• timeout, chunkTimeout, and transport are provider-only OpenCode policies.
• compaction remains shared: providers supply a default and models or variants may override it.
• Arbitrary provider-package settings remain available on providers, models, and variants.
• Core filters provider-only keys from model and variant overlays, then combines the provider and model settings only when constructing the runtime model.
• OpenAI, xAI, and Azure WebSocket defaults now live on provider settings.
• Client types, Protocol OpenAPI, website OpenAPI copies, configuration schema, tests, and documentation are regenerated.

Resolution

provider settings
├── timeout          provider only
├── chunkTimeout     provider only
├── transport        provider only
├── compaction       inherited by model
└── loose options    inherited by model
                       ↓
model settings
├── compaction       overrides provider
└── loose options    override provider
                       ↓
variant settings
├── compaction       overrides model
└── loose options    override model

The open index signature can accept any provider-defined key, including a spelling that matches an OpenCode policy. Core therefore explicitly removes timeout, chunkTimeout, and transport from model and variant overlays so only provider values control those behaviors.

Verification

• bun run check
• bun test in packages/schema — 64 passing
• focused Core provider, model, resolver, AI SDK, configuration, and built-in provider suites passing
• generated checks in packages/client, packages/protocol, and services/www
• bun run build in services/www

E2E tests were not run locally.