feat : plan 상세 조회 구현

src/main/java/com/github/cokothon/domain/plan/controller/PlanController.java

@@ -1,5 +1,6 @@
 package com.github.cokothon.domain.plan.controller;
 
+import com.github.cokothon.domain.plan.dto.response.GetPlanResponse;
 import org.springframework.security.access.prepost.PreAuthorize;
 import org.springframework.web.bind.annotation.DeleteMapping;
 import org.springframework.web.bind.annotation.GetMapping;
@@ -32,6 +33,13 @@ public ApiResponse<GetPlansResponse> getPlans() {
 		return ApiResponse.ok(planService.getPlans());
 	}
 
+	@GetMapping("/{planId}")
+	public ApiResponse<GetPlanResponse> getPlan(@PathVariable("planId") String planId) {
+
+
+		return ApiResponse.ok(planService.getPlan(planId));
+	}
+
 	@GetMapping("/best")
 	public ApiResponse<GetPlansResponse> getBestPlans() {
 

src/main/java/com/github/cokothon/domain/plan/dto/response/GetPlanResponse.java

@@ -0,0 +1,10 @@
+package com.github.cokothon.domain.plan.dto.response;
+
+import com.github.cokothon.domain.plan.schema.Plan;
+import lombok.Builder;
+
+@Builder
+public record GetPlanResponse(
+        Plan plan
+) {
+}

src/main/java/com/github/cokothon/domain/plan/service/PlanService.java

@@ -2,6 +2,7 @@
 
 import java.util.List;
 
+import com.github.cokothon.domain.plan.dto.response.GetPlanResponse;
 import org.springframework.data.domain.Sort;
 import org.springframework.data.mongodb.core.MongoTemplate;
 import org.springframework.data.mongodb.core.query.Query;
@@ -33,6 +34,16 @@ public GetPlansResponse getPlans() {
 							   .build();
 	}
 
+	public GetPlanResponse getPlan(String planId) {
+
+		Plan plan = planRepository.findById(planId)
+				.orElseThrow(PlanNotFoundException::new);
+
+		return GetPlanResponse.builder()
+				.plan(plan)
+				.build();
+	}
+
 	public GetPlansResponse getBestPlans() {
 
 		Query query = new Query()