feat(provider-surface): migrate SDK CLI docs to providers

[christso]

Summary

• Updates the SDK/programmatic eval authoring surface to use providers, provider, and default_test, with hard errors for old target authoring.
• Adds migration rewrites for target-shaped YAML into provider-shaped YAML, including .agentv/providers.yaml guidance and focused coverage.
• Updates CLI run/grade flags and docs/examples/templates to the provider public surface while preserving current internal run-artifact target vocabulary.

Validation

• bun test scripts/migrate-hard-deprecations.test.ts
• bun test packages/sdk/test/eval-authoring.test.ts
• bun test apps/cli/test/commands/eval/run-command-options.test.ts
• bun --filter @agentv/sdk typecheck
• bun --filter agentv typecheck
• git diff --check
• git diff --name-only --diff-filter=ACM -- "*.ts" "*.md" "*.mdx" "*.yaml" | xargs bunx biome format --write

Notes

• Left core parser/schema normalization files untouched for av-ctfu.
• Did not run broad example validation because provider-shaped authored YAML depends on the concurrent core provider-surface parser work.
• Live dogfood is not applicable for this isolated SDK/CLI/docs migration slice until the core provider authoring runtime lands.

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View logs

[christso]

CI triage update for this branch:

• Previous failing run: https://github.com/EntityProcess/agentv/actions/runs/28831912292
• Test failure was branch-local, not feat(core): normalize public providers schema #1708-blocked: the migration sweep had rewritten three core test fixtures that intentionally exercise removed authored YAML (expected_output and workspace.isolation). Fixed in f388b608 test(provider-surface): restore removed-field fixtures. Local validation now passes with bun --filter @agentv/core test (2304 pass, 0 fail), plus the earlier focused 3-file core test run.
• Validate Evals is blocked on feat(core): normalize public providers schema #1708 / av-ctfu: the job reported 55 invalid example eval files, all with [providers] Top-level providers is not a runtime alias in AgentV eval YAML..., because this PR intentionally migrates docs/examples to provider-shaped YAML while current main still rejects top-level providers.
• No parser/schema changes were made on this branch. Planned next step: after feat(core): normalize public providers schema #1708 merges, rebase this branch onto updated main and rerun the relevant validation/CI.

[christso]

CI follow-up for the rerun after f388b60:

• Test exposed one additional branch-local SDK failure in run 28833015259: packages/sdk/test/grader-helpers.test.ts still authored grader overrides as assertion target, and defineEval() correctly rejected eval.tests[0].assert[5].target.
• Fixed in 1438ab31 fix(sdk): emit grader provider overrides: SDK grader helpers now emit provider for LLM grader routing and script-grader proxy config, and nearby SDK/docs examples no longer show rejected target authoring.
• Local validation passed: bun test packages/sdk/test/grader-helpers.test.ts; bun --filter @agentv/sdk test (97 pass / 0 fail); bun --filter @agentv/sdk build; git diff --check; targeted scan for rejected docs keys in the touched docs scope.
• Validate Evals remains classified as blocked on feat(core): normalize public providers schema #1708 / av-ctfu. The provider-shaped authored YAML in this PR still needs the core parser/schema normalization from feat(core): normalize public providers schema #1708 before main CI can validate those examples. No parser/schema changes were made on this branch.

After #1708 merges: rebase this branch onto updated main and rerun validation/CI.

[christso]

Manual CI dispatch on the latest head 1438ab31: https://github.com/EntityProcess/agentv/actions/runs/28833666507

Result:

• Passed: Build, Typecheck, Lint, Check Links, Validate Marketplace, and Cloudflare Pages.
• Validate Evals failed as expected: 55/66 files still reject top-level providers on the current main parser/schema.
• Test still fails, but the remaining failures are now classified as feat(core): normalize public providers schema #1708-blocked core parser/schema dependency, not another self-contained SDK/CLI fix. The app/CLI tests use provider-shaped fixtures from this branch; current main core rejects them before the CLI assertions can run.

Representative Test failures:

• apps/cli/test/eval.integration.test.ts cases fail early with Invalid eval runtime config in eval file: top-level providers is not a runtime alias....
• apps/cli/test/commands/grade/grade-prepared.test.ts / prepare tests fail with .agentv/targets.yaml validation errors: [providers] Top-level providers is not a runtime alias in targets.yaml and [targets] Missing or invalid targets field.
• apps/cli/test/commands/eval/bundle.test.ts fails for the same current-core .agentv/targets.yaml parser rejection.

No parser/schema changes were made here. Next step remains: after #1708 lands, rebase this branch onto updated main and rerun CI/focused validation.