test: migrate from Jest to Vitest (Phase 1 complete)

- Remove Jest and all related packages
- Install Vitest with coverage support
- Create vitest.config.ts with path aliases
- Set up global test configuration
- Migrate all 6 test files to Vitest syntax
- Update TypeScript configuration for better Vitest support
- Create separate tsconfig.build.json for clean builds
- Fix all import/module issues in tests
- All 68 tests passing successfully
- Current coverage baseline: 2.45%

Phase 1 of testing suite improvement complete.

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

Co-Authored-By: Claude <noreply@anthropic.com>

src/http-server.ts

@@ -556,7 +556,10 @@ declare module './mcp/server' {
 }
 
 // Start if called directly
-if (require.main === module) {
+// Check if this file is being run directly (not imported)
+// In ES modules, we check import.meta.url against process.argv[1]
+// But since we're transpiling to CommonJS, we use the require.main check
+if (typeof require !== 'undefined' && require.main === module) {
   startFixedHTTPServer().catch(error => {
     logger.error('Failed to start Fixed HTTP server:', error);
     console.error('Failed to start Fixed HTTP server:', error);