workflow-fix: lint check for reserved [phase=done] multi-emission

Overview / Motivation

Auto-filed by the workflow-fix-on-bug protocol from a prose follow-up surfaced by the Claude code-reviewer on task #920 round 1.

Goal

Add a workflow_lint.py check (--check-phase-done-reserved, bundled into the no-flags default run) that FAILs when more than one [phase=done] emission site exists across a pod-side dispatcher and its phase scripts.

Workflow gap

• Bug observed: the #545 false-status=done class recurred in #920 r1: six phase scripts (issue920_gen_completions_b.py:295, issue920_extract_summaries.py:806, issue920_fit_lofo.py:548, issue920_nulls_figures.py:662,687, issue920_results_sentinel.py:145) each emitted the reserved [phase=done] token mid-pipeline into the main dispatcher log — the poller's done-detection would read a mid-run [phase=done] as run completion, masking later-phase crashes (binding on the RunPod failover rung).
• Why it is a workflow gap: .claude/rules/pod-side-reporting.md reserves [phase=done] for the dispatcher's terminal line, but nothing mechanical enforces single-emission — the class has now recurred despite the rule, and per-review catching is unreliable.
• Confidence (emitter): medium

Proposed change (candidate diff sketch — refine in planning)

+ def check_phase_done_reserved() -> list[str]:
+     # For each scripts/issue*_dispatch.sh, collect its phase scripts
+     # (uv run python scripts/<name>.py invocations); grep dispatcher +
+     # phase scripts for literal "[phase=done]" emission sites (echo /
+     # logger / print). >1 site per dispatcher family => FAIL listing
+     # each file:line. Allowlist: the dispatcher terminal line.
+ (bundle into the no-flags default run; add tests)

Scope / surfaces

• Primary target: scripts/workflow_lint.py
• Grep the workflow surface for the pattern before editing (grep -rln 'phase=done' scripts/ .claude/) and update every hit; list them in the plan.

Constraints / invariants

• Workflow-surface only — never experiment code, configs/, or tasks/ (the lint READS scripts/issue* but the change lands in workflow_lint.py + tests).
• scripts/workflow_lint.py --check-asks passes; ruff on touched files passes.
• This session runs under EPM_WORKFLOW_FIX_SESSION=1 and carries a workflow_fix_target: Provenance line — it MUST NOT auto-route any of its own subagents' workflow-fix candidates (recursion guard).

Provenance

• workflow_fix_target: scripts/workflow_lint.py
• fingerprint: e309ff7733a6

Surfaced prose (code-reviewer #920 r1, verbatim): "a workflow_lint.py --check-phase-done-reserved check flagging >1 [phase=done] emission site across a dispatcher + its phase scripts — the #545 class has now recurred despite the pod-side-reporting rule."