Summary

• Rebuilds the native provider package work as one clean PR on top of current dev.
• Adds the LLM provider package contract and native provider entrypoints.
• Flattens provider/model config and schema around package, modelID, settings, headers, and body.
• Migrates core catalog/config/session runner to the flat package shape.
• Preserves aisdk: compatibility through the existing AI SDK provider hooks until catalog producers move to native packages.
• Regenerates current client and legacy JS SDK types.

Supersedes the conflicted consolidated branch/PR #34461; existing stacked branches/PRs are left untouched.

Validation

• bun typecheck from packages/core
• bun typecheck from packages/schema
• bun typecheck from packages/llm
• bun typecheck from packages/client
• bun typecheck from packages/sdk/js
• bun test test/session-runner-model.test.ts test/plugin/provider-google.test.ts test/config/provider-options.test.ts test/config/provider.test.ts test/catalog.test.ts test/config/config.test.ts from packages/core
• bun test test/provider-package.test.ts test/exports.test.ts from packages/llm
• bun test test/contract-hygiene.test.ts from packages/schema
• pre-push workspace typecheck: 29 successful, 29 total