fix: 搜索 tag 过滤改用 cast(ARRAY(Uuid))，杜绝 asyncpg 把 ARRAY[$n] 推断成 text[] 导致 uuid[] && text[] 500（根因在 year_counts 子查询复用 conditions）

backend/app/services/search_engine.py

@@ -4,7 +4,7 @@ import logging
 import re
 from datetime import datetime
 
-from sqlalchemy import String, and_, case, cast, exists, func, literal_column, not_, or_, select, text
+from sqlalchemy import ARRAY, String, Uuid, and_, case, cast, exists, func, literal_column, not_, or_, select, text
 
 logger = logging.getLogger(__name__)
 from sqlalchemy.ext.asyncio import AsyncSession
@@ -506,9 +506,11 @@ class AdvancedSearchEngine:
                 child_conds = [GlobalTag.path.like(f"{p}%") for p in paths]
                 children = (await db.execute(select(GlobalTag.id).where(or_(*child_conds)))).scalars().all()
                 all_tag_ids.update(children)
-            uids = list(all_tag_ids)
-            from sqlalchemy.dialects.postgresql import array as _pg_array, UUID as _pg_uuid
-            conditions.append(GlobalLiterature.tag_ids.overlap(_pg_array(uids, type_=_pg_uuid())))
+            uids = [_uuid.UUID(u) if isinstance(u, str) else u for u in all_tag_ids]
+            # 显式 cast 到 ARRAY(Uuid)：不依赖 _pg_array 的参数类型推断（asyncpg prepared
+            # statement 会把 ARRAY[$n] 推断成 text[]，导致 uuid[] && text[] 500）。cast 后
+            # 编译产物必带 ::uuid[]，杜绝推断漂移。
+            conditions.append(GlobalLiterature.tag_ids.overlap(cast(uids, ARRAY(Uuid))))
 
         # 发表类型（PG JSONB contains）
         if pub_types: