The planner workflow (`graphlemon-node-1858572453964d2389959e82e9b2fd3b`) completed. It produced a Benchmark/acceptance-test document for the pending task: adding a one-line rationale comment above `_BUSY_TIMEOUT_MS = 30000` in `src/scheduler.py`, cross-referencing (not duplicating) the existing sqlite busy-timeout explanation already in the module docstring (lines 21-28).

Key points from the benchmark:
- **Scenario 1 (happy path):** exactly one added comment line directly above the constant, cross-referencing (not copying) the docstring; `_FIX_LOOP_TIMEOUT` untouched; `py_compile` passes.
- **Scenario 2 (boundary):** if the comment is already present, re-running produces a zero-diff result rather than stacking a duplicate comment — this directly addresses the previously-noted "pipeline lacks a zero-diff terminal state" gap for this exact comment-already-present pattern.
- **Scenario 3 (scope guard):** only `src/scheduler.py` changes, exactly +1 line, no other files/constants touched.

No code was written — this was planner scope only (SDD → Benchmark). The output is ready to hand to a Coder node if the actual edit still needs to be applied.