Add fast API unit tests for pre-commit hooks

Overview

Implement fast unit tests that can run in pre-commit hooks to catch API issues before commits. Current tests are too slow for pre-commit use.

Requirements

• Tests should complete in < 3 seconds
• Test all 60+ API endpoints
• Validate schemas and route registration
• Mock external dependencies (DB, Redis)
• Run only on changed files when possible

Recommended Implementation

Use Vitest with mocked dependencies for speed (~1-2ms per endpoint)

Tasks

• [ ] Install Vitest and testing dependencies
• [ ] Create vitest.config.ts with optimized settings
• [ ] Write fast endpoint tests using OpenAPI spec
• [ ] Mock database and Redis connections
• [ ] Add pre-commit hook with Husky
• [ ] Configure lint-staged for selective testing
• [ ] Add test:pre-commit script to package.json
• [ ] Document testing approach in README

Expected Outcome

• Pre-commit tests run in < 3 seconds
• All endpoints validated against OpenAPI spec
• Schema validation without external dependencies
• Catches breaking changes before commit

Performance Targets

• Unit tests: < 5 seconds for full suite
• Changed files only: < 1 second
• Pre-commit hook: < 3 seconds total

Related: #testing #dx #performance