feat: add About Me dialog showing user info, roles, and groups

- Add GET /api/v1/auth/me endpoint returning current user's UserDetail
- Add AboutMeDialog component with role badges and group memberships
- Add userMenuItems prop to TopBar via design-system update
- Wire "About Me" menu item into user dropdown above Logout

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cameleer3-server-app/src/main/java/com/cameleer3/server/app/security/UiAuthController.java

@@ -7,6 +7,7 @@ import com.cameleer3.server.core.admin.AuditResult;
 import com.cameleer3.server.core.admin.AuditService;
 import com.cameleer3.server.core.rbac.RbacService;
 import com.cameleer3.server.core.rbac.SystemRole;
+import com.cameleer3.server.core.rbac.UserDetail;
 import com.cameleer3.server.core.security.JwtService;
 import jakarta.servlet.http.HttpServletRequest;
 import com.cameleer3.server.core.security.JwtService.JwtValidationResult;
@@ -22,6 +23,8 @@ import org.slf4j.LoggerFactory;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
+import org.springframework.security.core.Authentication;
+import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
@@ -149,6 +152,21 @@ public class UiAuthController {
         }
     }
 
+    @GetMapping("/me")
+    @Operation(summary = "Get current user details")
+    @ApiResponse(responseCode = "200", description = "Current user details")
+    @ApiResponse(responseCode = "401", description = "Not authenticated")
+    public ResponseEntity<UserDetail> me(Authentication authentication) {
+        if (authentication == null || authentication.getName() == null) {
+            throw new ResponseStatusException(HttpStatus.UNAUTHORIZED, "Not authenticated");
+        }
+        UserDetail detail = rbacService.getUser(authentication.getName());
+        if (detail == null) {
+            throw new ResponseStatusException(HttpStatus.UNAUTHORIZED, "User not found");
+        }
+        return ResponseEntity.ok(detail);
+    }
+
     public record LoginRequest(String username, String password) {}
     public record RefreshRequest(String refreshToken) {}
 }