[BOOK-168] chore: API 경로에서 불필요한 슬래시 제거

Author: seoyoon513

core/network/src/main/kotlin/com/ninecraft/booket/core/network/service/ReedService.kt

@@ -66,7 +66,7 @@ interface ReedService {
     ): LibraryResponse
 
     // Reading-records endpoints (auth required)
-    @POST("/api/v1/reading-records/{userBookId}")
+    @POST("api/v1/reading-records/{userBookId}")
     suspend fun postRecord(
         @Path("userBookId") userBookId: String,
         @Body recordRegisterRequest: RecordRegisterRequest,