feat: wire ReplayStatsTracker into SessionController + complete GraphView.updateTrend

src/pygui/backend/models/replay_stats.py

@@ -0,0 +1,37 @@
+import numpy as np
+
+
+class ReplayStatsTracker:
+    """Accumulates per-frames statistic acrossa replay session."""
+
+    def __init__(self) -> None:
+        self.history: list[dict] = []
+        self.running_avg: float = 0.0
+
+    def track(self, frame_index: int, temperatures: list[float]) -> dict:
+        arr = np.array(temperatures, dtype = np.float32)
+        clean_arr = arr[np.isfinite(arr)]
+
+        if clean_arr.size == 0:
+            stats = {"frame": frame_index, "min":0.0, "max":0.0, "avg":0.0, "std":0.0}
+        else:
+            stats = {
+                "frame": frame_index,
+                "min": float(np.min(clean_arr)),
+                "max": float(np.max(clean_arr)),
+                "avg": float(np.mean(clean_arr)),
+                "std": float(np.std(clean_arr)),
+            }
+
+        self.history.append(stats)
+        if self.history:
+            self.running_avg = float(np.mean([s["avg"] for s in self.history]))
+        return stats
+
+    def get_trend(self) -> list[float]:
+        """Return list of per-frame average for trend chat"""
+        return [s["avg"] for s in self.history]
+
+    def reset(self) -> None:
+        self.history.clear()
+        self.running_avg = 0.0