fix(workspace_files): right = VBox(100%x100%) + fixed-height droppable + filler VScrollPanel file list

wwwroot/api/workspace_files.dspy

@@ -43,17 +43,15 @@ upload_script = (
     "if(rb){var cid=rb.current_id;rb.current_id=undefined;await rb.render_browser(cid);}"
 )
 
-widgets = []
-
-# 拖拽上传区
-widgets.append({
+# 拖拽上传区（固定高度）
+droppable = {
     "widgettype": "Droppable",
     "options": {"accepts": ["*"], "padding": "10px"},
     "subwidgets": [
         {"widgettype": "Text", "options": {"text": "📥 拖拽文件到此处上传", "cfontsize": 0.85, "color": "#64748b", "halign": "middle"}}
     ],
     "binds": [{"wid": "self", "event": "filedrop", "actiontype": "script", "target": "self", "script": upload_script}]
-})
+}
 
 files = []
 try:
@@ -98,12 +96,19 @@ for name in entries:
         files.append(row)
 
 if not files:
-    widgets.append({"widgettype": "Text", "options": {"text": "(空目录)", "cfontsize": 0.85, "color": "#94a3b8", "padding": "8px"}})
+    file_list_content = [{"widgettype": "Text", "options": {"text": "(空目录)", "cfontsize": 0.85, "color": "#94a3b8", "padding": "8px"}}]
 else:
-    widgets.extend(files)
+    file_list_content = files
+
+# 文件列表区：filler + VScrollPanel（占满剩余高度并可滚动）
+file_list_panel = {
+    "widgettype": "VScrollPanel",
+    "options": {"css": "filler", "width": "100%"},
+    "subwidgets": file_list_content
+}
 
 return {
     "widgettype": "VBox",
-    "options": {"width": "100%", "padding": "8px", "gap": "6px"},
-    "subwidgets": widgets
+    "options": {"width": "100%", "height": "100%", "padding": "8px", "gap": "6px"},
+    "subwidgets": [droppable, file_list_panel]
 }