feat: Wafer Map integration

## Backend — Session & playback
- Add SessionController (QML-facing live/review controller) with
  loadedFile property for active-file highlight binding
- Add SessionModel, FramePlayer, and CsvRecorder for state machine,
  frame seek/step/speed, and CSV recording
- Add SensorEditor for per-sensor value overrides (replace + offset)

src/pygui/backend/csv_recorder.py

@@ -0,0 +1,46 @@
+"""Append live frames"""
+from __future__ import annotations
+from datetime import datetime
+from pathlib import Path
+from typing import Optional, TextIO
+
+
+from pygui.backend.frame import Frame
+from pygui.backend.zwafer_models import Sensor
+
+class CsvRecorder:
+    def __init__(self) -> None:
+        self._file_handle: Optional[TextIO] = None
+        self._oath: Optional[str] = None
+        
+        
+    @property
+    def is_recording(self) -> bool:
+            return self._file_handle is not None
+        
+        
+    def start(self, path: str, sensors:list[Sensor], serial: str = "") -> None:
+        Path(path).parent.mkdir(parents=True, exist_ok=True)
+        file_handle = open(path, "w", encoding="utf-8", newline ="")
+        file_handle.write(f"Wafer ID={serial}\n")
+        file_handle.write(f"Acquisition Date={datetime.now():%m/%d/%Y}\n")
+        file_handle.write("Label," + ",".join(s.label for s in sensors) + "\n")
+        file_handle.write("X (mm)," + ",".join(str(s.x) for s in sensors) + "\n")
+        file_handle.write("Y (mm)," + ",".join(str(s.y) for s in sensors) + "\n")
+        file_handle.write("data\n")
+        file_handle.flush()
+        self._file_handle, self._path = file_handle, path
+        
+    def write(self, frame: Frame) ->  None:
+        if self._file_handle is None:
+            return
+        row = [f"{frame.time:.3f}"] + [f"{v:.3f}" for v in frame.values]
+        self._file_handle.write(",".join(row) + "\n")
+        self._file_handle.flush()
+        
+    def stop(self) -> Optional[str]:
+        if self._file_handle is None:
+            return None
+        self._file_handle.close()
+        path, self._file_handle, self._path = self._path, None, None
+        return path