enhance(#4570): allow disabling planner stall detection (#4585)

* enhance(#4570): allow disabling planner stall detection

* docs(#4570): add changelog fragment

Emitted-Drift-Ack-Growth: plan-phase.md — the explicit opt-out gate covers all five planner and checker spawn classes
Emitted-Drift-Ack-Growth: settings-advanced.md — the toggle prompt and bounded-recovery warning expose the new setting

* chore(#4570): refresh compact-content baseline

* fix(#4570): preserve default-on watchdog fallback

* docs(#4570): qualify the chunked-mode orchestrator rules with the toggle

The two chunked-planning-mode stall-watch imperatives read as
unconditional, with the opt-out stated only in a following bullet. State
the PLANNER_STALL_DETECTION_ENABLED condition inline, matching the three
sites already qualified in plan-phase.md.

* chore(#4570): refresh compact-content baselines against rebased next

* fix(#4570): sync planner stall launcher

Keep the stall-detection helper aligned with the canonical runtime launcher.

* chore(#4570): refresh compact baseline after rebase

---------

Co-authored-by: Tom Boucher <trekkie@nomorestars.com>

docs/zh-CN/references/planning-config.md

@@ -24,6 +24,12 @@
 | `git.milestone_branch_template` | `"gsd/{milestone}-{slug}"` | 里程碑策略的分支模板 |
 </config_schema>
 
+<planner_stall_detection>
+
+`planner.stall_detection_enabled` 默认为 `true`，控制标准规划器、分块规划器、计划检查器和修订规划器的有界停滞检测。运行 `gsd config-set planner.stall_detection_enabled false` 可跳过 watchdog 轮询，并通过运行时原生完成机制等待每个 agent。**警告：** `false` 会放弃运行时丢失完成回传时的有界恢复；可能需要中断并使用现有文件系统回退。
+
+</planner_stall_detection>
+
 <commit_docs_behavior>
 
 **当 `commit_docs: true`（默认）：**
@@ -197,4 +203,4 @@ fi
 
 </branching_strategy_behavior>
 
-</planning_config>
+</planning_config>