refactor(types): unify handler and middleware definitions

- Consolidates `Handler` and `Middleware` types under `Types` module
- Replaces `IHandler` and `IMiddleware` interfaces with typed functions
- Simplifies imports and improves code organization
- Enhances debugging with named handlers and middlewares

src/Utils/createRouteMatcher.ts

@@ -35,7 +35,9 @@ export function createRouteMatcher(
         // 3b. Extract route params
         const params: Params = {};
         for (const [key, value] of Object.entries(result.pathname.groups)) {
-            params[key] = value ?? ''; // null → empty string
+            if (value) {
+                params[key] = value;
+            }
         }
 
         // 3c. Extract query parameters – keep duplicates as arrays