fix: _current_conv bei RowHighlighted asynchron laden (QR + Delete)

tui/screens/main_screen.py

@@ -164,10 +164,18 @@ class MainScreen(Screen):
     # ── Events ─────────────────────────────────────────────────────────────────
 
     def on_data_table_row_highlighted(self, event: DataTable.RowHighlighted) -> None:
-        """Cursor-Bewegung: conv_id sofort merken (für d-Taste etc.)."""
+        """Cursor-Bewegung: conv_id und conv sofort merken (für d/t-Taste etc.)."""
         conv_id = self._conv_id_map.get(event.cursor_row)
         if conv_id:
             self._current_conv_id = conv_id
+            # _current_conv asynchron nachladen
+            asyncio.create_task(self._fetch_current_conv(conv_id))
+
+    async def _fetch_current_conv(self, conv_id: str) -> None:
+        try:
+            self._current_conv = await self._api.get_conversation(conv_id)
+        except Exception:
+            pass
 
     async def on_data_table_row_selected(self, event: DataTable.RowSelected) -> None:
         row_idx = event.cursor_row