fix(tests): address edge cases in mock infrastructure

- Prevent spy leak on double mockFetch() call
- Differentiate body types (URLSearchParams, ArrayBuffer, Blob, ReadableStream)
- Fix route path parsing to preserve spaces
- Escape regex special chars before wildcard replacement
- Remove unused MockResponse.error and MockRoute interface

tests/mocks/types.ts

@@ -21,23 +21,11 @@ export interface MockResponse {
   headers?: Record<string, string>;
   /** Delay in ms before responding (for timeout testing) */
   delay?: number;
-  /** Throw error instead of responding */
-  error?: Error;
 }
 
 /** Route key format: "METHOD /path" */
 export type RouteKey = `${HttpMethod} ${string}`;
 
-/** Mock route configuration */
-export interface MockRoute {
-  /** HTTP method */
-  method: HttpMethod;
-  /** URL path pattern (string or regex) */
-  path: string | RegExp;
-  /** Response to return */
-  response: MockResponse;
-}
-
 /** Configuration for createMockHttpServer */
 export interface MockHttpServerConfig {
   /** Route definitions - key format: "METHOD /path" */