feat: Add SMK evaluator to TypeScript SDK

[adnanrhussain]

Summary

This PR implements the Subject Matter Knowledge evaluator to the TypeScript SDK

Documentation

See sdks/typescript/README.md

Testing

• CI workflow should build successfully

[codecov]

Codecov Report

❌ Patch coverage is 87.50000% with 7 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
sdks/typescript/src/evaluators/smk.ts	84.09%	7 Missing ⚠️

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[Copilot]

Pull request overview

Adds a new Subject Matter Knowledge (SMK) evaluator to the TypeScript SDK and wires it into the existing composite TextComplexityEvaluator, along with docs and tests.

Changes:

• Introduces SmkEvaluator (Google Gemini) with prompt + Zod schema and functional API export.
• Extends TextComplexityEvaluator to run vocabulary, sentence structure, and SMK in parallel and return subjectMatterKnowledge.
• Adds unit + integration tests and updates SDK README + changelogs.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
sdks/typescript/tests/unit/evaluators/text-complexity.test.ts	Updates unit tests to include SMK sub-evaluator behavior and 3-way parallelism expectations.
sdks/typescript/tests/unit/evaluators/smk.test.ts	Adds unit tests for SMK evaluator validation, metadata, mapping, and error propagation.
sdks/typescript/tests/integration/smk.integration.test.ts	Adds integration coverage for SMK across grades 3–12 using dataset-derived cases.
sdks/typescript/src/schemas/smk.ts	Defines the structured SMK response schema and SmkInternal type.
sdks/typescript/src/prompts/subject-matter-knowledge/index.ts	Adds prompt getters that inline shared prompt text assets.
sdks/typescript/src/index.ts	Exposes SMK evaluator and internal types from the package entrypoint.
sdks/typescript/src/evaluators/text-complexity.ts	Adds SMK as a third sub-evaluator and includes it in the returned result map.
sdks/typescript/src/evaluators/smk.ts	Implements the SMK evaluator and functional evaluateSmk API.
sdks/typescript/src/evaluators/index.ts	Re-exports SMK evaluator and functional API from the evaluators barrel.
sdks/typescript/README.md	Documents the new SMK evaluator and updates Text Complexity docs to include SMK.
sdks/typescript/CHANGELOG.md	Adds a release entry describing SMK and composite changes.
evals/prompts/subject-matter-knowledge/user.txt	Adds the SMK user prompt template.
evals/prompts/subject-matter-knowledge/system.txt	Adds the SMK system prompt (rubric + output contract).
evals/prompts/CHANGELOG.md	Records the new SMK prompt addition.

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