fix: reset visible run logs for new runs

app/gui/tabs/apply.py

@@ -146,7 +146,7 @@ class ApplyTab(QWidget):
         self.write_back_button.clicked.connect(self.write_back_results)
 
         self.refresh_tasks()
-        self._load_latest_run_log()
+        self._show_current_run_log_empty()
 
     def _set_status(self, message):
         if self.status_callback is not None:
@@ -279,7 +279,7 @@ class ApplyTab(QWidget):
         self.apply_worker = worker
         self.apply_thread = thread
         self._set_apply_running(True)
-        self.run_log_view.clear()
+        self._reset_run_log(tasks, dry_run=dry_run, batch_size=batch_size)
         if dry_run:
             self._set_status(f"开始检查本轮更新：{len(tasks)} 条")
         else:
@@ -626,6 +626,18 @@ class ApplyTab(QWidget):
 
     def _append_run_log(self, message):
         self.run_log_view.appendPlainText(str(message))
+        scroll_bar = self.run_log_view.verticalScrollBar()
+        scroll_bar.setValue(scroll_bar.maximum())
+
+    def _show_current_run_log_empty(self):
+        self.run_log_view.setPlainText("本轮日志会在开始运行后显示")
+
+    def _reset_run_log(self, tasks, dry_run=False, batch_size=1):
+        self.run_log_view.clear()
+        action = "检查" if dry_run else "更新"
+        self._append_run_log(
+            f"本轮{action}开始：任务 {len(tasks)} 条，每批 {batch_size} 条"
+        )
 
     def _load_latest_run_log(self):
         try: