feat(chat): add transient presence flash and 5s reconnect grace period

backend/chat/src/handlers/handlers_test.go

@@ -951,6 +951,32 @@ func TestHandleAdminChatLog_FilterByRoom(t *testing.T) {
 	}
 }
 
+func TestHandleAdminChatLog_ExcludesSystem(t *testing.T) {
+	deps, gormDB, _ := setupTestDeps(t)
+
+	gormDB.Create(&db.Message{Room: "main", Username: "system", Text: "bob joined main", Timestamp: time.Now(), Type: "system"})
+	gormDB.Create(&db.Message{Room: "main", Username: "u1", Text: "hello", Timestamp: time.Now(), Type: "public"})
+
+	handler := HandleAdminChatLog(deps)
+	req := httptest.NewRequest("GET", "/api/admin/chat-log", nil)
+	w := httptest.NewRecorder()
+
+	handler(w, req)
+
+	if w.Code != http.StatusOK {
+		t.Errorf("status = %d, want 200", w.Code)
+	}
+
+	var resp ChatLogListResponse
+	json.NewDecoder(w.Body).Decode(&resp)
+	if resp.Total != 1 {
+		t.Errorf("Total = %d, want 1 (system messages must be excluded)", resp.Total)
+	}
+	if len(resp.Entries) != 1 || resp.Entries[0].Text != "hello" {
+		t.Errorf("entries = %v, want only the public chat message", resp.Entries)
+	}
+}
+
 func TestHandleAdminChatLogByID_Get(t *testing.T) {
 	deps, gormDB, _ := setupTestDeps(t)