Preserve the final clean precheck receipt

Why: Retain the strict READY check before freezing the documentation candidate.

Evidence: make evidence captured the complete precheck output with exact source and target.

Impact: Task metadata only; final CI remains required.

Refs: PR #651

.task/feature-conversation-handoff.md

@@ -366,3 +366,42 @@
 - host Review 对同步后 11245d172c6841a17696a041889b8dbc4d8807a7 完成：相对 origin/main 的业务差异只有 AGENTS.md 一行与 policy/delivery.md 新增 22 行，另有本任务记录；现行 AGENT-EXECUTION.md 与其它 policy 无回退。
 - 需求 R1 的七项 handoff 字段、无续办例外、证据权威边界和入口链接均直接复核通过。文档没有新增平台功能，不制造业务测试。真实模型行为前后量化 NOT_RUN；当前规范交付以可审条款、链接和 GATE 为依据，不声称完成行为评测。
 - main 同步原始输出、文档检查与递归组合输出均由 make evidence 原样写入本卡。最终候选固定后只保存在源码外记录，避免为回填 CI 再改变 HEAD。
+
+<!-- Local receipt: SELF. Digests detect corruption; they do not authenticate a reviewer or CI. -->
+```json
+{
+  "summary_schema": 1,
+  "source": "SELF",
+  "timestamp": "2026-10-20T09:23:34.774230+00:00",
+  "command": "make precheck",
+  "exit_code": 0,
+  "cwd": "/home/weichen/projects/Agent-System-Dev-wt-feature-conversation-handoff",
+  "before_head": "2aad4bc2acf0cf7fb29ce5df604bcaff83c054bd",
+  "after_head": "2aad4bc2acf0cf7fb29ce5df604bcaff83c054bd",
+  "branch": "feature/conversation-handoff",
+  "target_branch": "main",
+  "target_head": "17f8bc06c110014b9101e7a33729d9f5445bd123",
+  "root_target": "main",
+  "immediate_target": "main",
+  "before_tracked_diff_sha256": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+  "after_tracked_diff_sha256": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+  "output_tail": [
+    "make[1]: Entering directory '/home/weichen/projects/Agent-System-Dev-wt-feature-conversation-handoff'",
+    "[repo]   branch=feature/conversation-handoff head=2aad4bc2ac",
+    "[remote] origin/main=17f8bc06c1 ahead=11 behind=0",
+    "[tree]   clean submodules_drift=0 uninit=0",
+    "[worktrees] linked=6",
+    "[initiatives] local cards (not authoritative): none",
+    "[hooks]   core.hooksPath=scripts/hooks（pre-commit/post-merge 实际接线）",
+    "[facts]   policy/facts.md 6 条事实均在有效期内",
+    "[required-reading] core/baseline.md, workflows/delivery.md §1, policy/delivery.md",
+    "[R0] 17f8bc06c1（完整：17f8bc06c110014b9101e7a33729d9f5445bd123）",
+    "[worktree] before-sync: recursive component checks passed",
+    "[verdict] READY — 保留本次 precheck receipt 后建任务工作区：PRECHECK_RECEIPT=/tmp/task-precheck.json make task-start NAME=feature/your-branch",
+    "make[1]: Leaving directory '/home/weichen/projects/Agent-System-Dev-wt-feature-conversation-handoff'"
+  ],
+  "output_sha256": "df04e4a972fd4f2eec24c391d8892c85698ca0f00fe9950df3d4b91c27df48a2",
+  "receipt_sha256": "f676ac17f42a3634b98cc3287cb7f891df70b5361970c14c4bd3dcd77a6290fa",
+  "receipt_path": "/home/weichen/.cache/agent-system-dev/evidence/f676ac17f42a3634b98cc3287cb7f891df70b5361970c14c4bd3dcd77a6290fa.json"
+}
+```