fix(evolution): allow backlog re-queue after executed

[cursor]

Summary

• Fixes a critical evolution governance break: after a proposal is marked executed, the same dedupe_key could never re-enter evolution_backlog because dedupe_key was globally UNIQUE while upsert only updated non-executed rows.
• Concrete trigger: authorize capability evolution for tool/outcome X → run succeeds (executed) → authorize the same gap again → enqueue returns a phantom proposal_id → forced evolution run logs evolution_proposal_missing and returns NoScope.
• Approach: migrate away the global UNIQUE, upsert active rows or insert when only executed history remains, and remap coordinator status updates to the persisted active proposal id.

Bug and Impact

• Bug: Soft-dedupe schema contradicted soft-dedupe logic; executed history permanently blocked re-queue.
• Impact: User-authorized re-evolution (and same-scope follow-up proposals) silently fails after the first execution for that key.

Root Cause

• evolution_backlog.dedupe_key TEXT NOT NULL UNIQUE + INSERT OR IGNORE + UPDATE ... WHERE status != 'executed' → both arms no-op once an executed row exists.

Task Linkage

• Task ID: TASK-2026-084
• Task folder: tasks/TASK-2026-084-evolution-backlog-requeue-after-executed/

Injected Specs

• spec/verification-integrity.md
• spec/task-artifact-language.md
• spec/architecture-boundaries.md
• spec/structured-signal-first.md
• spec/capability-gap-evolution.md
• spec/rust-conventions.md
• spec/testing-policy.md
• spec/security-nonnegotiables.md (N/A)
• spec/docs-sync.md (N/A: no user-facing docs/command/env change)

Validation Evidence

• Commands executed:
  • cargo test -p skilllite-evolution --lib → 97 passed
  • cargo clippy -p skilllite-evolution --all-targets -- -D warnings → clean
  • python3 scripts/validate_tasks.py → 71 task directories passed
• Key results:
  • enqueue_user_capability_evolution_requeues_after_executed ok
  • migrate_evolution_backlog_allows_requeue_with_legacy_unique_dedupe ok
  • coordinate_attaches_status_to_persisted_id_after_requeue ok
  • Existing soft-dedupe test still ok

Regression Scope

• Areas likely affected:
  • Evolution backlog upsert / authorize-capability / coordinator status attach
  • Existing feedback.sqlite DBs (one-time table rebuild when UNIQUE present)
• Explicit non-goals:
  • sessions.json concurrent write merge
  • Open path-escape / workspace-scoping PR backlog (fix(evolution): constrain pending skill path operations #89, Fix Linux sandbox filtered network fail-open #112–fix(chat): prevent session transcript/plan prefix collisions #135)

Docs Sync (EN/ZH)

• Not needed

Review Checklist

• Acceptance criteria in tasks/TASK-2026-084-evolution-backlog-requeue-after-executed/TASK.md satisfied
• STATUS.md updated
• REVIEW.md includes merge readiness decision
• tasks/board.md status is up to date