fix(kanban): prevent false task completion with QC verifier scoring gate

[zhanglib1996]

Problem

Workers completing Kanban tasks had no quality gate — any task that called kanban_complete immediately transitioned to done regardless of output quality, correctness, or completeness. This allowed false task completion to go undetected.

Refs: NousResearch#25288, NousResearch#21925

Solution

A new qc_review status sits between running/ready and done. Tasks created with require_qc=true enter qc_review upon completion instead of done. A verifier (agent or human) calls kanban_review to approve or reject.

Database layer

• VALID_STATUSES: Added qc_review
• Schema migration (auto, safe for existing DBs): require_qc (INTEGER), qc_threshold (REAL), qc_score (REAL), rework_count (INTEGER), last_qc_feedback (TEXT)
• create_task(): Accepts require_qc (bool) and qc_threshold (float)
• complete_task(): Reads require_qc before write txn; transitions to qc_review instead of done when QC is required; emits completed_awaiting_qc event
• qc_approve(): qc_review → done with score + feedback
• qc_reject(): qc_review → ready (or → blocked after 3 rework cycles) with feedback

Tool layer

• kanban_review (new orchestrator tool): approve/reject with score (0.0–1.0) and feedback
• kanban_create: New require_qc + qc_threshold params
• kanban_complete: Returns status: qc_review in OK response when QC gate engaged
• All list/show tools surface QC fields

Notification layer

• Gateway watcher subscribes to completed_awaiting_qc events
• Renders: 🔍 Kanban {id} done — awaiting QC review (threshold: 0.7)

Usage

# Create a task that requires QC
kanban_create(title="verify login flow", assignee="dev", require_qc=true, qc_threshold=0.8)

# ... worker completes, task enters qc_review instead of done ...

# QC verifier approves
kanban_review(task_id="t_abc123", approve=true, score=0.9, feedback="All checks pass")

# Or rejects for rework
kanban_review(task_id="t_abc123", approve=false, score=0.4, feedback="Missing error handling on line 42")

Backward Compatibility

• Existing tasks without require_qc behave exactly as before (straight to done)
• All new columns have defaults (NULL/0) — zero migration burden

[zhanglib1996]

superseded: resubmitting to upstream NousResearch/hermes-agent