fix(im): preserve platform event error semantics

im-service/src/main/java/com/xuqm/im/controller/PlatformEventController.java

@@ -25,7 +25,6 @@ public class PlatformEventController {
     public ResponseEntity<ApiResponse<Map<String, String>>> token(
             @RequestParam String appKey,
             @RequestParam(defaultValue = "platform") String userId) {
-        try {
         String userSig = accountService.generateUserSigToken(appKey, userId, 24 * 60 * 60, "");
         ImAccountService.LoginResult result = accountService.loginWithUserSig(appKey, userId, userSig);
         Map<String, String> data = new LinkedHashMap<>();
@@ -34,8 +33,5 @@ public class PlatformEventController {
         data.put("token", result.token());
         data.put("admin", String.valueOf(result.admin()));
         return ResponseEntity.ok(ApiResponse.success(data));
-        } catch (Exception e) {
-            return ResponseEntity.status(500).body(ApiResponse.error(500, e.getMessage()));
-        }
     }
 }

im-service/src/test/java/com/xuqm/im/controller/PlatformEventControllerTest.java

@@ -0,0 +1,29 @@
+package com.xuqm.im.controller;
+
+import com.xuqm.common.exception.BusinessException;
+import com.xuqm.im.service.ImAccountService;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+class PlatformEventControllerTest {
+
+    @Test
+    void preservesBusinessExceptionForTheSharedErrorHandler() {
+        BusinessException expected = new BusinessException(404, "应用不存在");
+        ImAccountService accountService = new ImAccountService(null, null, null) {
+            @Override
+            public String generateUserSigToken(String appKey, String userId, long expireSeconds, String userBuf) {
+                throw expected;
+            }
+        };
+
+        PlatformEventController controller = new PlatformEventController(accountService);
+
+        BusinessException actual = assertThrows(
+                BusinessException.class,
+                () -> controller.token("missing-app", "platform"));
+        assertSame(expected, actual);
+    }
+}