fix(ai-outfit): preview sample rows ignore Excel status (§19.9)

Add excel_service.read_all_rows (every valid data row, status-independent) and
use it in _reload_sample_rows for the preview dropdown, so previewing still
works after the whole sheet is 完成. Generation still uses load_outfit_tasks.
+1 excel test (read_all_rows includes 完成/失败, skips incomplete); offscreen
all-完成 sheet now yields sample rows; full suite (12) green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/widgets/ai_outfit_panel.py

@@ -636,17 +636,20 @@ class AiOutfitPanel(QWidget):
         self._refresh_preview()
 
     def _reload_sample_rows(self):
-        """Best-effort: read the chosen Excel to fill the sample dropdown."""
+        """Best-effort: read the chosen Excel to fill the sample dropdown.
+
+        Uses read_all_rows (status-independent) so preview still works after the
+        whole sheet is 完成 (docs/11 §10.3); generation still uses load_outfit_tasks.
+        """
         excel = self._excel_edit.text().strip()
-        tasks = []
+        rows = []
         if excel:
             try:
-                from services.excel_service import load_outfit_tasks
-                tasks = load_outfit_tasks(
-                    excel, retry_failed=self._retry_failed_chk.isChecked())
+                from services.excel_service import read_all_rows
+                rows = read_all_rows(excel)
             except Exception as exc:                     # noqa: BLE001 - silent for preview
                 logger.info("Sample rows unavailable: %s", exc)
-        self._fill_sample_combo(tasks)
+        self._fill_sample_combo(rows)
 
     def _refresh_preview(self):
         if not hasattr(self, "_preview_view"):