Pin the script host, deferred tools, and background MCP connect

Why: the shared Python host and the MCP connect change landed in the libraries the product already calls.
Evidence: native, squad, and backend feature commits are recorded on the task card.
Impact: gitlinks move to those commits. Code orchestration stays off unless the setting is turned on.
Refs: feature/code-orchestration
Co-authored-by: Cursor <cursoragent@cursor.com>

.task/feature-code-orchestration.md

@@ -21,6 +21,6 @@
 
 ## 结果与验证（完成后填写）
 
-- 结果：
-- 验证：
-- 影响与剩余项：
+- 结果：native e4020d2，squad dcd523e，backend cd57276。
+- 验证：native `go test` 覆盖 codeorch、tools、mcp、policy、adapters/native。backend `go test` 覆盖 runtime、app、settings、tools、runmgr。组合验证见后续 make test。
+- 影响与剩余项：`runtime.codeOrchestration` 默认关。延迟工具不进清单。MCP 未连上时后台连接，已连上则当场注册。