Add vitest related to pre-commit with expensive test skipping (#7854)

## Summary
This PR improves the pre-commit hook performance by:
- Using `vitest related` to run only tests affected by changed files
- Adding ability to skip expensive tests (filter tests) during
pre-commit
- Providing a consistent mechanism for skipping expensive tests

## Changes
- Modified `lint-staged.config.mjs` to run `vitest related` with
`SKIP_EXPENSIVE_TESTS=true`
- Updated `test/filter-tests.ts` to use idiomatic `describe.skipIf()`
for conditional test execution
- Changed `test-min` script to use `SKIP_EXPENSIVE_TESTS` environment
variable instead of `--exclude`
- Updated `CLAUDE.md` with documentation about the new test workflow

## Impact
- Pre-commit hooks are now much faster as they:
  - Only run tests related to changed files
  - Skip 688 expensive filter tests
  - Use the same skipping mechanism as `npm run test-min`

## Testing
- ✅ Verified `vitest related` correctly identifies and runs related
tests
- ✅ Confirmed filter tests are skipped when `SKIP_EXPENSIVE_TESTS=true`
- ✅ Tested that full test suite still runs all tests when env var is not
set
- ✅ Pre-commit hooks work correctly with the new setup

🤖 Generated with [Claude Code](https://claude.ai/code)

---------

Co-authored-by: Claude <noreply@anthropic.com>

CLAUDE.md

@@ -84,6 +84,13 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
   - Write platform-specific assertions
   - Use path-agnostic checks
 
+### Test Execution with Expensive Test Skipping
+- The `SKIP_EXPENSIVE_TESTS=true` environment variable skips expensive tests (like filter tests)
+- Pre-commit hooks use `vitest related` to run only tests related to changed files
+- Use `npm run test-min` to run tests with expensive tests skipped
+- Use `npm run test` to run all tests including expensive ones
+- To mark tests as expensive, use: `describe.skipIf(process.env.SKIP_EXPENSIVE_TESTS === 'true')('Test suite', () => {...})`
+
 ## Compiler Testing Specifics
 - Mock filesystem operations when testing file I/O
 - Use `makeFakeCompilerInfo()` for creating test compiler configurations