Implement BAT-009 manual asset CRUD and snapshot close

tests/contract_snapshots/response_contract_v1_0.json

@@ -64,6 +64,38 @@
         "success": "bool",
         "account": {"type": "dict", "required": {"id": "str", "name": "str", "type": "str", "active": "bool"}}
       }
+    },
+    "manual_asset_mutation": {
+      "required": {
+        "success": "bool",
+        "manual_asset": {"type": "dict", "required": {"id": "str", "name": "str", "active": "bool", "valuation_date": "str", "liquidity_bucket": "str", "source_note": "str"}}
+      }
+    },
+    "asset_snapshot_preview": {
+      "required": {
+        "success": "bool",
+        "basis_date": "str",
+        "source": "str",
+        "is_closed_snapshot": "bool",
+        "total_assets": "int",
+        "total_liabilities": "int",
+        "net_worth": "int",
+        "warnings": "list"
+      }
+    },
+    "asset_snapshot_close": {
+      "required": {
+        "success": "bool",
+        "basis_date": "str",
+        "source": "str",
+        "is_closed_snapshot": "bool",
+        "snapshot_run_id": "str",
+        "is_correction": "bool",
+        "inserted_count": "int",
+        "total_assets": "int",
+        "total_liabilities": "int",
+        "net_worth": "int"
+      }
     }
   }
 }