fix(T+): 补齐指导成本与读取服务保护

补充业务详情指导成本入口、来源版本和历史封存保护，接入月份锁并完善权限复核。
同步接入读取服务运行状态到页面，补充前端控制、回归测试和服务端只读连接授权校验。

定向隔离测试：89 项通过，1 条既有 Starlette 弃用警告。

backend/tests/integration/test_tplus_sync_console.py

@@ -13,9 +13,10 @@ pytestmark = pytest.mark.integration
 BASE = "/api/v1/system/tplus"
 
 
-def test_新增配置表迁移可往返且不修改同步批次():
+def test_不可逆迁移拒绝回退且不修改同步批次():
     from alembic import command
     from alembic.config import Config
+    from alembic.script import ScriptDirectory
     from sqlalchemy import inspect, text
 
     from app.core.db import get_engine
@@ -25,12 +26,12 @@ def test_新增配置表迁移可往返且不修改同步批次():
     with engine.connect() as connection:
         before = connection.exec_driver_sql('SELECT COUNT(*) FROM tplus_sync_batches').scalar_one()
     config = Config(str(Path(__file__).resolve().parents[2] / "alembic.ini"))
-    command.downgrade(config, "26e7f8a9b0c1")
-    assert not inspect(engine).has_table("tplus_automation_configs")
+    with pytest.raises(RuntimeError, match="不可直接回退"):
+        command.downgrade(config, "26e7f8a9b0c1")
     command.upgrade(config, "head")
     assert inspect(engine).has_table("tplus_automation_configs")
     with engine.connect() as connection:
-        assert connection.execute(text('SELECT version_num FROM alembic_version')).scalar_one() == '28a9b0c1d2e3'
+        assert connection.execute(text('SELECT version_num FROM alembic_version')).scalar_one() == ScriptDirectory.from_config(config).get_current_head()
         assert connection.exec_driver_sql('SELECT COUNT(*) FROM tplus_sync_batches').scalar_one() == before