feat(export): batch wafer-map PNG export from file list

- BatchExport worker + BatchExportController (threaded, busy flag)
- SourcePanel: Export Maps button → FolderDialog → batch export
  with progress/summary banner (dismissible)
- StreamControlPanel: name single export after loaded CSV + timestamp

src/pygui/backend/wafer/batch_export.py

@@ -0,0 +1,68 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from datetime import datetime
+from pathlib import Path
+
+from pygui.backend.data.data_records import (
+    is_official_csv,
+    read_data_records,
+    read_official_csv,
+)
+from pygui.backend.models.frame_player import frames_from_wafer_data
+from pygui.backend.visualization.wafer_map_item import WaferMapItem
+from pygui.backend.wafer.zwafer_parser import ZWaferParser
+
+_EXPORT_SIZE = 600
+
+
+@dataclass
+class BatchExportResult:
+    file_path: str
+    output_path: str
+    success: bool
+    error: str = ""
+
+
+def export_batch(
+    file_paths: list[str], output_dir: str, timestamp: str | None = None
+) -> list[BatchExportResult]:
+    """Render the last frame of each file to a PNG in output_dir.
+
+    Skips files that fail to parse or render, continuing with the rest.
+    """
+    ts = timestamp or datetime.now().strftime("%Y%m%d_%H%M%S")
+    results = []
+    for file_path in file_paths:
+        results.append(_export_one(file_path, output_dir, ts))
+    return results
+
+
+def _export_one(file_path: str, output_dir: str, ts: str) -> BatchExportResult:
+    base_name = Path(file_path).stem
+    output_path = str(Path(output_dir) / f"{base_name}_{ts}.png")
+    try:
+        if is_official_csv(file_path):
+            sensors, records = read_official_csv(file_path)
+        else:
+            data, _ = ZWaferParser().parse(file_path)
+            if data is None or not data.sensors:
+                return BatchExportResult(file_path, output_path, False, "Invalid layout or missing sensors")
+            sensors = data.sensors
+            records = read_data_records(file_path)
+
+        frames = frames_from_wafer_data(None, records)
+        if not sensors or not frames:
+            return BatchExportResult(file_path, output_path, False, "No sensors or frames found")
+
+        item = WaferMapItem()
+        item.setWidth(_EXPORT_SIZE)
+        item.setHeight(_EXPORT_SIZE)
+        item.sensors = [{"label": s.label, "x": s.x, "y": s.y} for s in sensors]  # type: ignore[method-assign]
+        item.values = frames[-1].values  # type: ignore[method-assign]
+
+        if not item.export_image(output_path):
+            return BatchExportResult(file_path, output_path, False, "Export render failed")
+        return BatchExportResult(file_path, output_path, True)
+    except Exception as exc:
+        return BatchExportResult(file_path, output_path, False, str(exc))