fix(search): 将搜索历史持久化到应用数据库

backend/app/services/search_history.py

@@ -0,0 +1,23 @@
+from contextlib import closing
+
+from app.database.db import connect, transaction
+
+
+def list_queries():
+    with closing(connect()) as conn:
+        return [row['query'] for row in conn.execute('SELECT query FROM search_history ORDER BY id DESC LIMIT 10')]
+
+
+def record(query: str):
+    query = query.strip()
+    if not query:
+        return
+    with closing(connect()) as conn, transaction(conn):
+        conn.execute('DELETE FROM search_history WHERE query=?', (query,))
+        conn.execute('INSERT INTO search_history(query) VALUES (?)', (query,))
+        conn.execute('DELETE FROM search_history WHERE id NOT IN (SELECT id FROM search_history ORDER BY id DESC LIMIT 10)')
+
+
+def clear():
+    with closing(connect()) as conn, transaction(conn):
+        conn.execute('DELETE FROM search_history')