v1.7.9: Add comprehensive CORS preflight handling and module middleware support

CORS Improvements:

• Add automatic OPTIONS preflight handling with 204 response
• Implement dynamic origin validation with sync/async function support
• Add origin rejection with 403 status for failed validation
• Support string, array, boolean, and function origin types
• Add preflightContinue option for manual preflight handling
• Add comprehensive CORS tests (26 tests, all passing)

Module Middleware:

• Add module-level middleware (applied to all routes in module)
• Add route-level middleware (applied to specific routes)
• Support middleware as string names or functions
• Add middleware resolution from MiddlewareManager and builtInMiddleware
• Implement proper execution order: global → module → route → handler
• Add safe middleware getter to MiddlewareManager
• Add comprehensive module middleware tests (12 tests, all passing)

Documentation:

• Update MIDDLEWARE_GUIDE.md with CORS dynamic origin examples
• Update API.md with CORS function examples
• Update CONFIGURATION_REFERENCE.md with CORS options
• Update MODULES_GUIDE.md with complete middleware section
• Add execution order and built-in middleware reference

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Breaking Changes: None
All 604 tests passing
Backward compatible