feat(ci): add TypeScript type checking to CI

[Copilot]

The build step only type-checks files included in compilation. Test files are excluded via tsconfig.json (**/*.test.ts), leaving 32 test files unchecked for type errors.

Changes

• tsconfig.check.json: New config extending base tsconfig, includes both src/**/*.ts and tests/**/*.ts
• package.json: Added type-check script for local use
• .github/workflows/test-integration.yml: New workflow running type check on PRs and pushes to main

Usage

# Local type checking (all files including tests)
npm run type-check

# CI runs automatically on PRs

Execution time: ~2.5 seconds locally.

Original prompt

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This section details on the original issue you should resolve

<issue_title>[plan] add typescript type checking to ci/cd</issue_title>
<issue_description>## Objective

Add explicit TypeScript type checking to CI/CD using tsc --noEmit to catch type errors in all files, including tests.

Context

The build step runs npm run build which compiles TypeScript, but:

• Only type-checks files included in the build
• Tests are excluded (tsconfig.json excludes **/*.test.ts)
• Type errors in non-compiled files could be missed

Implementation Approach

Add a type-check job to .github/workflows/test-integration.yml:

type-check:
  name: TypeScript Type Check
  runs-on: ubuntu-latest
  steps:
    - uses: actions/checkout@v4
    - uses: actions/setup-node@v4
      with:
        node-version: '22'
        cache: 'npm'
    - run: npm ci
    - run: npx tsc --noEmit

The --noEmit flag validates types without generating output files, catching errors in all TypeScript files including tests.

Files to Modify

• .github/workflows/test-integration.yml - Add type-check job

Acceptance Criteria

• Type check job runs on all PRs
• Validates types in src/ and tests/ directories
• Fails if any TypeScript errors found
• Completes in under 1 minute

Estimated Effort

15 minutes - Single job addition to workflow
Related to #294

AI generated by Plan Command for discussion #270

Comments on the Issue (you are @copilot in this section)

• Fixes [plan] add typescript type checking to ci/cd #296

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[github-actions]

✅ Coverage Check Passed

Overall Coverage

Metric	Base	PR	Delta
Lines	77.26%	77.26%	➡️ +0.00%
Statements	77.34%	77.34%	➡️ +0.00%
Functions	77.17%	77.17%	➡️ +0.00%
Branches	69.81%	69.81%	➡️ +0.00%

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Coverage comparison generated by scripts/ci/compare-coverage.ts