归档10-05错误码可解释性与付款就绪任务（09-05-error-explainability-payment-readiness）

591条历史豁免基线已清零，794条新增reasonCode已通过候选分支合并落地至
origin/main（46a70aa5），主链路零例外，无剩余阻塞验收项。
work landed via 已删除的候选分支而非专属分支，故用
--skip-branch-validation 归档。

.trellis/tasks/archive/2026-09/09-05-error-explainability-payment-readiness/implement.jsonl

@@ -0,0 +1 @@
+{"_example": "Fill with {\"file\": \"<path>\", \"reason\": \"<why>\"}. Put spec/research files only — no code paths. Run `python3 .trellis/scripts/get_context.py --mode packages` to list available specs. Delete this line once real entries are added."}