Reinforce series-qa as diagnosis-only with longform handoff

[Hanjo92]

Summary

Reinforce series-qa as a diagnosis-only skill that isolates failures and hands deeper recovery work to longform-story-design.

Problem

series-qa currently diagnoses well, but some wording still drifts toward revision planning. After strengthening longform-story-design for long-range audit + recovery, series-qa should become sharper, not broader.

Goal

• Keep series-qa focused on diagnosis, evidence, severity, and recheck gates
• Let it suggest repair direction only at a high level
• Hand canon recovery, reconstruction packages, and drafting re-entry work to longform-story-design

Scope

• skills/series-qa/SKILL.md
• skills/series-qa/references/diagnostic-workflow.md
• skills/series-qa/references/report-templates.md
• skills/series-qa/references/regression-checks.md
• optionally skills/series-qa/references/example-prompts.md

Planned changes

1. Add hard diagnosis-only boundaries near the top of the skill
2. Add a canonical diagnostic order ending in handoff
3. Narrow the output contract to QA artifacts
4. Standardize repair direction plus handoff target language
5. Tighten recheck output so it distinguishes QA pass vs. needs recovery planning

Acceptance criteria

• The skill reads as diagnosis-only from the opening section
• It does not imply ownership of reconstruction packages or drafting re-entry packets
• Major findings include evidence, root cause, damage, repair direction, and handoff target
• Templates remain practical QA artifacts rather than redesign plans
• Recheck output verifies the original failure mode is gone

Design doc

• docs/superpowers/specs/2026-04-14-series-qa-diagnostic-handoff-design.md