Test suite modernization:
- Converted all try/finally cleanup patterns to beforeEach/afterEach hooks
across 11 test files (core, copilot-install, config, workstream,
milestone-summary, forensics, state, antigravity, profile-pipeline,
workspace)
- Consolidated 40 inline mkdtempSync calls to use centralized helpers
- Added createTempDir() helper for bare temp directories
- Added optional prefix parameter to createTempProject/createTempGitProject
- Fixed config test HOME sandboxing (was reading global defaults.json)
New CONTRIBUTING.md:
- Test standards: hooks over try/finally, centralized helpers, HOME sandboxing
- Node 22/24 compatibility requirements with Node 26 forward-compat
- Code style, PR guidelines, security practices
- File structure overview
All 1382 tests pass, 0 failures.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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