Promotes queryParams to a first-class ModelRef field used by Endpoint.baseURL,
so deployment-level URL query params (Azure api-version, OpenAI-compatible
provider knobs) live in a typed home instead of an opaque `native` bag.
Also removes write-only dead fields from `native`:
- openaiCompatibleProvider (set by family helper, never read)
- opencodeProviderID, opencodeModelID (set by opencode bridge + native session
builder, never read)
- npm (set by opencode bridge, never read)
After this commit `model.native` only carries genuinely provider-specific
opaque options that no other adapter cares about (Bedrock's aws_credentials
+ aws_region for SigV4). Drops the now-dead ProviderShared.queryParams
helper. Updates AGENTS.md doc on native is implicit through the new schema
JSDoc.
Kit Langton
f86a6790a2