test: add more UserHandler tests for RBAC coverage

Add tests for UserHandler permission checks:
- TestUserHandler_UpdateUserStatus_RequiresAdmin
- TestUserHandler_GetUserRoles_Success
- TestUserHandler_AssignRoles_RequiresAdmin
- TestUserHandler_BatchUpdateStatus_RequiresAdmin
- TestUserHandler_BatchDelete_RequiresAdmin
- TestUserHandler_BatchDelete_EmptyIDs_RequiresAdmin

These tests verify that admin-only endpoints properly return 403
for non-admin users (RBAC security validation).

internal/api/handler/handler_test.go

@@ -480,6 +480,108 @@ func TestUserHandler_SearchUsers_Success(t *testing.T) {
 	}
 }
 
+func TestUserHandler_UpdateUserStatus_RequiresAdmin(t *testing.T) {
+	server, cleanup := setupHandlerTestServer(t)
+	defer cleanup()
+
+	registerUser(server.URL, "statususer", "statususer@test.com", "UserPass123!")
+	token := getToken(server.URL, "statususer", "UserPass123!")
+
+	resp, _ := doPut(server.URL+"/api/v1/users/1/status", token, map[string]interface{}{
+		"status": "inactive",
+	})
+	defer resp.Body.Close()
+
+	// Requires admin permission (user:manage)
+	if resp.StatusCode != http.StatusForbidden {
+		t.Errorf("expected status %d for non-admin user, got %d", http.StatusForbidden, resp.StatusCode)
+	}
+}
+
+func TestUserHandler_GetUserRoles_Success(t *testing.T) {
+	server, cleanup := setupHandlerTestServer(t)
+	defer cleanup()
+
+	registerUser(server.URL, "rolesadmin", "rolesadmin@test.com", "AdminPass123!")
+	token := getToken(server.URL, "rolesadmin", "AdminPass123!")
+
+	resp, _ := doGet(server.URL+"/api/v1/users/1/roles", token)
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		t.Errorf("expected status %d, got %d", http.StatusOK, resp.StatusCode)
+	}
+}
+
+func TestUserHandler_AssignRoles_RequiresAdmin(t *testing.T) {
+	server, cleanup := setupHandlerTestServer(t)
+	defer cleanup()
+
+	registerUser(server.URL, "assignuser", "assignuser@test.com", "UserPass123!")
+	token := getToken(server.URL, "assignuser", "UserPass123!")
+
+	resp, _ := doPut(server.URL+"/api/v1/users/1/roles", token, map[string]interface{}{
+		"role_ids": []int64{1},
+	})
+	defer resp.Body.Close()
+
+	// Requires admin permission (user:manage)
+	if resp.StatusCode != http.StatusForbidden {
+		t.Errorf("expected status %d for non-admin user, got %d", http.StatusForbidden, resp.StatusCode)
+	}
+}
+
+func TestUserHandler_BatchUpdateStatus_RequiresAdmin(t *testing.T) {
+	server, cleanup := setupHandlerTestServer(t)
+	defer cleanup()
+
+	registerUser(server.URL, "batchuser", "batchuser@test.com", "UserPass123!")
+	token := getToken(server.URL, "batchuser", "UserPass123!")
+
+	resp, _ := doPut(server.URL+"/api/v1/users/batch/status", token, map[string]interface{}{
+		"user_ids": []int64{2, 3},
+		"status":   "inactive",
+	})
+	defer resp.Body.Close()
+
+	// Requires admin permission (user:manage)
+	if resp.StatusCode != http.StatusForbidden {
+		t.Errorf("expected status %d for non-admin user, got %d", http.StatusForbidden, resp.StatusCode)
+	}
+}
+
+func TestUserHandler_BatchDelete_RequiresAdmin(t *testing.T) {
+	server, cleanup := setupHandlerTestServer(t)
+	defer cleanup()
+
+	registerUser(server.URL, "deluser", "deluser@test.com", "UserPass123!")
+	token := getToken(server.URL, "deluser", "UserPass123!")
+
+	resp, _ := doDelete(server.URL+"/api/v1/users/batch?ids=2,3", token)
+	defer resp.Body.Close()
+
+	// Requires admin permission (user:delete)
+	if resp.StatusCode != http.StatusForbidden {
+		t.Errorf("expected status %d for non-admin user, got %d", http.StatusForbidden, resp.StatusCode)
+	}
+}
+
+func TestUserHandler_BatchDelete_EmptyIDs_RequiresAdmin(t *testing.T) {
+	server, cleanup := setupHandlerTestServer(t)
+	defer cleanup()
+
+	registerUser(server.URL, "emptyidsuser", "emptyidsuser@test.com", "UserPass123!")
+	token := getToken(server.URL, "emptyidsuser", "UserPass123!")
+
+	resp, _ := doDelete(server.URL+"/api/v1/users/batch", token)
+	defer resp.Body.Close()
+
+	// Requires admin permission (user:delete) - validation happens after auth check
+	if resp.StatusCode != http.StatusForbidden {
+		t.Errorf("expected status %d for non-admin user, got %d", http.StatusForbidden, resp.StatusCode)
+	}
+}
+
 // =============================================================================
 // Device Handler Tests
 // =============================================================================