fix(db): 补回 system_configs.description 列（修复 /admin/config 500）

- 此前 MySQL 适配时模型编辑误删 description，导致仓储序列化 AttributeError
- 0037_system_config_description：幂等补列（SQLite 已有则跳过）并回填存量说明
- 与并行的 0037_market 分叉建 merge 版本，统一迁移线（当前 head=02d10eccb1f9）

alembic/versions/0037_system_config_description.py

@@ -0,0 +1,44 @@
+"""补回 system_configs.description（此前模型编辑误删，导致 /admin/config 500）。
+
+Revision ID: 0037_system_config_description
+Revises: 0036_service_orders
+Create Date: 2026-08-31
+"""
+from __future__ import annotations
+
+import sqlalchemy as sa
+from alembic import op
+
+revision = "0037_system_config_description"
+down_revision = "0036_service_orders"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    """SQLite 已有该列 → 仅 MySQL/缺失时补；幂等（查列存在性）。"""
+    bind = op.get_bind()
+    insp = sa.inspect(bind)
+    cols = [c["name"] for c in insp.get_columns("system_configs")]
+    if "description" not in cols:
+        op.add_column("system_configs", sa.Column("description", sa.String(), nullable=True, server_default=""))
+        # 从 SQLite 备份源回填说明（如存在）
+        try:
+            import sqlite3
+            from pathlib import Path
+            db_path = Path("serverdata/data/app.db")
+            if db_path.exists():
+                sconn = sqlite3.connect(str(db_path))
+                rows = sconn.execute("SELECT key, description FROM system_configs").fetchall()
+                sconn.close()
+                from sqlalchemy import text
+                for k, d in rows:
+                    if d:
+                        bind.execute(text("UPDATE system_configs SET description=:d WHERE `key`=:k"),
+                                     {"d": d, "k": k})
+        except Exception:  # noqa: BLE001 回填失败不阻塞
+            pass
+
+
+def downgrade() -> None:
+    pass  # 保留列（回滚会造成数据丢失）

alembic/versions/02d10eccb1f9_merge_market_与_system_config_.py

@@ -0,0 +1,25 @@
+"""merge market 与 system_config_description 分支
+
+Revision ID: 02d10eccb1f9
+Revises: 0037_market, 0037_system_config_description
+Create Date: 2026-08-31 23:44:52.597833
+
+"""
+from __future__ import annotations
+
+import sqlalchemy as sa
+from alembic import op
+
+
+revision = '02d10eccb1f9'
+down_revision = ('0037_market', '0037_system_config_description')
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    pass
+
+
+def downgrade() -> None:
+    pass

app/infrastructure/models.py

@@ -388,6 +388,7 @@ class SystemConfig(Base):
 
     key: Mapped[str] = mapped_column(String, primary_key=True)
     value: Mapped[str] = mapped_column(Text, default="")  # 配置值（存量可达 300+ 字节，MySQL 用 MEDIUMTEXT）
+    description: Mapped[str] = mapped_column(String, default="")   # 配置说明（0037 补回：此前模型误删）
     updated_at: Mapped[str] = mapped_column(String, default="")