docs(backend): add Springdoc Swagger UI OpenAPI documentation

backend/pom.xml

@@ -32,6 +32,11 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-validation</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.springdoc</groupId>
+            <artifactId>springdoc-openapi-starter-webmvc-ui</artifactId>
+            <version>2.8.5</version>
+        </dependency>
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-test</artifactId>
@@ -79,4 +84,4 @@
             </plugin>
         </plugins>
     </build>
-</project>
+</project>

backend/src/main/java/com/algorithmrace/visualizer/controller/CatalogController.java

@@ -2,21 +2,30 @@
 
 import com.algorithmrace.visualizer.dto.CatalogResponse;
 import com.algorithmrace.visualizer.service.CatalogService;
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.tags.Tag;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
 @RestController
 @RequestMapping("/api/catalog")
+@Tag(name = "Catalog", description = "Endpoints for retrieving supported algorithms and metadata")
 public class CatalogController {
     private final CatalogService catalogService;
 
     public CatalogController(CatalogService catalogService) {
         this.catalogService = catalogService;
     }
 
+    @Operation(
+        summary = "Get algorithm catalog", 
+        description = "Retrieves the full catalog of available sorting, searching, and pathfinding algorithms along with their metadata."
+    )
+    @ApiResponse(responseCode = "200", description = "Successfully retrieved catalog")
     @GetMapping
     public CatalogResponse catalog() {
         return catalogService.catalog();
     }
-}
+}

backend/src/main/java/com/algorithmrace/visualizer/controller/SimulationController.java

@@ -5,6 +5,9 @@
 import com.algorithmrace.visualizer.dto.SearchingSimulationRequest;
 import com.algorithmrace.visualizer.dto.SortingSimulationRequest;
 import com.algorithmrace.visualizer.service.SimulationService;
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.tags.Tag;
 import jakarta.validation.Valid;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;
@@ -13,25 +16,41 @@
 
 @RestController
 @RequestMapping("/api/simulations")
+@Tag(name = "Simulations", description = "Endpoints for running algorithm race simulations")
 public class SimulationController {
     private final SimulationService simulationService;
 
     public SimulationController(SimulationService simulationService) {
         this.simulationService = simulationService;
     }
 
+    @Operation(
+        summary = "Run sorting simulation", 
+        description = "Executes sorting algorithm simulations and returns step-by-step race performance data."
+    )
+    @ApiResponse(responseCode = "200", description = "Sorting simulation executed successfully")
     @PostMapping("/sorting")
     public RaceResponse sorting(@Valid @RequestBody SortingSimulationRequest request) {
         return simulationService.simulateSorting(request);
     }
 
+    @Operation(
+        summary = "Run searching simulation", 
+        description = "Executes searching algorithm simulations and returns step-by-step race performance data."
+    )
+    @ApiResponse(responseCode = "200", description = "Searching simulation executed successfully")
     @PostMapping("/searching")
     public RaceResponse searching(@Valid @RequestBody SearchingSimulationRequest request) {
         return simulationService.simulateSearching(request);
     }
 
+    @Operation(
+        summary = "Run pathfinding simulation", 
+        description = "Executes pathfinding algorithm simulations and returns step-by-step race performance data."
+    )
+    @ApiResponse(responseCode = "200", description = "Pathfinding simulation executed successfully")
     @PostMapping("/pathfinding")
     public RaceResponse pathfinding(@Valid @RequestBody PathfindingSimulationRequest request) {
         return simulationService.simulatePathfinding(request);
     }
-}
+}

backend/src/main/resources/application.yml

@@ -18,6 +18,9 @@ app:
   cors:
     allowed-origins: ${CORS_ALLOWED_ORIGINS:http://localhost:5173,https://algorithm-race-visualizer.vercel.app}
 
+springdoc:
+  swagger-ui:
+    path: /swagger-ui.html
 
 management:
   endpoints:
@@ -26,4 +29,4 @@ management:
         include: health
   endpoint:
     health:
-      show-details: never
+      show-details: never