fix: try/except around DB queries (Agent 2 review)

wwwroot/knowledge_bases_list/file_list.dspy

@@ -10,7 +10,8 @@ db = DBPools()
 dbname = get_module_dbname('rag')
 
 rows = []
-async with db.sqlorContext(dbname) as sor:
+try:
+    async with db.sqlorContext(dbname) as sor:
         if folder_id:
             recs = await sor.sqlExe(
                 "SELECT id, file_name, file_type, file_size, file_path, status, chunk_count, created_at FROM documents WHERE kb_id=${kb_id}$ AND folder_id=${folder_id}$ ORDER BY created_at DESC",
@@ -30,6 +31,8 @@ async with db.sqlorContext(dbname) as sor:
                 "chunk_count": r.chunk_count or 0,
                 "created_at": str(r.created_at)[:16] if r.created_at else ''
             })
+except:
+    return json.dumps({"widgettype": "Text", "options": {"text": "加载文件列表失败", "cfontsize": 14, "color": "#e74c3c", "halign": "center", "marginTop": "40px"}}, ensure_ascii=False)
 
 def fmt_size(sz):
     if sz < 1024: return str(sz) + "B"

wwwroot/knowledge_bases_list/get_tree_data.dspy

@@ -3,7 +3,8 @@ id = ns.get('id')
 kb_id = ns.get('kb_id', '')
 db = DBPools()
 dbname = get_module_dbname('rag')
-async with db.sqlorContext(dbname) as sor:
+try:
+    async with db.sqlorContext(dbname) as sor:
         if not id:
             recs = await sor.sqlExe(
                 "SELECT id, '' as parentid, content as label FROM document_chunks WHERE kb_id=${kb_id}$ AND chunk_type='directory' AND (description IS NULL OR description='') ORDER BY content",
@@ -17,4 +18,6 @@ async with db.sqlorContext(dbname) as sor:
                 "SELECT id, description as parentid, content as label FROM document_chunks WHERE kb_id=${kb_id}$ AND chunk_type='directory' AND description=${id}$ ORDER BY content",
                 {"kb_id": kb_id, "id": id})
             return [dict(r) for r in recs]
+except:
+    return [{"id": "__root__", "parentid": "", "label": "📁 根目录（加载失败）"}]
 return []