debug

以系统化流程定位并修复代码根本原因，保留复现与回归测试。

按步骤定位并修复代码的根本原因：先复现（最好做成失败的测试），列假设并验证、并行排查、证伪直到找到真正原因，再修复并保留回归测试与经验记录。遇到间歇性或复杂错误时用最靠谱，特点是流程化、可复现且把教训留在仓库里，避免又犯同样的坑。

## Progress Contract

Register these steps as a native task list at Step 1, before beginning.
Report progress as "N steps remaining, size class S/M/L" — never wall-clock ETAs.

Register steps in the native task list named `🐙 <n>/<total> — <step name>`; update each to in_progress/completed as you go — the checklist is the user's primary progress view.

Steps: (1) reproduce, (2) hypothesize, (3) falsify, (4) fix, (5) lesson.

**Hard rule: no fix without a confirmed root cause and a repro.**

## Workflow

### Step 1 — Reproduce

Construct a minimal reproduction case. Prefer a failing automated test; if a test is not
feasible, document the exact command or sequence that triggers the bug.

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