Fix verdict parsing + plug stale-task enforcement hole

- task.py: remove naive substring fallback from parse_verdict_status(),
  only parse ## Status: header; no header → ambiguous (REFEREE)
- status.py: add _auto_update_verdict_on_complete() — when transitioning
  human_intervention→complete, auto-update VERDICT.md to PASS
- status.py: add stale-task detection to --can-edit — deny edits if
  all edit tasks have .state mtime >30 min old (reason: stale_task)
- status.py: add --touch command to reset task activity clock
- guard plugin: handle stale_task reason with specific error message
- Update test to match new verdict parsing behavior

tasks/fix-verdict-parsing-fallback/.state

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+complete

tasks/fix-verdict-parsing-fallback/ADVERSARIAL_BUG_FIND.md

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+# ADVERSARIAL BUG FIND

tasks/fix-verdict-parsing-fallback/ADVERSARIAL_BUG_REPORT.md

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+# ADVERSARIAL

tasks/fix-verdict-parsing-fallback/BUG_FIND.md

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+# BUG FIND

tasks/fix-verdict-parsing-fallback/BUG_REPORT.md

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+# BUG_REPORT

tasks/fix-verdict-parsing-fallback/DOC_REVIEW.md

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+# DOC

tasks/fix-verdict-parsing-fallback/IMPLEMENTATION.md

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+# IMPLEMENTATION\n\nFixed verdict parsing and auto-update.

tasks/fix-verdict-parsing-fallback/REFEREE.md

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+# REFEREE

tasks/fix-verdict-parsing-fallback/SPEC.md

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+# Fix Verdict Parsing\n\nRemove naive substring fallback. Add auto-update on human_intervention→complete.

tasks/fix-verdict-parsing-fallback/VERDICT.md

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+VERDICT: PASS