Add get router by id endpoint

src/main/java/com/litoralregas/openvpn/router/RouterController.java

@@ -4,6 +4,7 @@ import jakarta.validation.Valid;
 import org.springframework.web.bind.annotation.*;
 
 import java.util.List;
+import java.util.UUID;
 
 @RestController
 @RequestMapping("/api/routers")
@@ -24,4 +25,9 @@ public class RouterController {
     public Router create(@Valid @RequestBody CreateRouterRequest request) {
         return service.create(request);
     }
+
+    @GetMapping("/{id}")
+    public Router getById(@PathVariable UUID id) {
+        return service.findById(id);
+    }
 }

src/main/java/com/litoralregas/openvpn/router/RouterService.java

@@ -38,4 +38,9 @@ public class RouterService {
 
         return repository.save(router);
     }
+
+    public Router findById(UUID id) {
+        return repository.findById(id)
+                .orElseThrow(() -> new IllegalArgumentException("Router not found: " + id));
+    }
 }