fix(sdk): align eval config providers surface - #1722

Summary

TypeScript eval authoring now follows the same Promptfoo-shaped provider surface as YAML. SDK users can author providers entries with id/label, select defaults.provider and defaults.grader, and set grader providers through defaultTest.options.provider, tests[].options.provider, or assertion-level provider without falling back to top-level target, targets, or graders.

The TS eval loader no longer rewrites YAML-aligned target into providers; stale target-era eval files now fail with provider migration guidance. options.provider is also carried into LLM-backed assertions as the inherited grader provider, while assertion-level provider still wins.

The remaining target-named SDK API is createTargetClient() and related target-proxy types. Those are documented as runtime-only script-grader proxy APIs, not eval authoring syntax.

Validation

• bun test packages/sdk/test/eval-authoring.test.ts
• bun test packages/core/test/evaluation/loaders/ts-eval-loader.test.ts packages/core/test/evaluation/loaders/grader-parser.test.ts
• bun --filter @agentv/core typecheck
• bun --filter @agentv/sdk typecheck
• bunx biome check ...touched files...
• bun --filter @agentv/sdk test
• bun --filter @agentv/sdk build

Live dogfood was attempted after copying .env from the primary checkout. It is blocked locally: eval-file inline providers are still ignored by the current CLI provider resolution path covered by #1718, catalog openai starts but fails with pi-ai call failed: Connection error, and catalog local-openai requires missing LOCAL_OPENAI_PROXY_API_KEY.

Related

Related: av-icbt
Related: #1718, #1719