fix: init cpuCores with correct count on first stat tick regardless of consumers

modules/SystemStats.qml

@@ -72,6 +72,13 @@ QtObject {
                                     history: hist.length > histLen ? hist.slice(hist.length - histLen) : hist
                                 };
                             });
+                        } else if (root.cpuCores.length !== ev.cores.length) {
+                            // Keep count in sync so panel can size correctly before consumers activate
+                            root.cpuCores = ev.cores.map(c => ({
+                                        "usage": c.usage,
+                                        "freq_ghz": c.freq_ghz,
+                                        "history": []
+                                    }));
                         }
                     } else if (ev.type === "temp") {
                         root.tempCelsius = ev.celsius;