feat: add cc-taskrunner plugin — autonomous task queue

[stackbilt-admin]

Summary

Adds cc-taskrunner, a plugin that turns Claude Code into an autonomous task execution system with safety guarantees.

• Queue tasks and run them unattended (overnight, during meetings, in CI)
• Branch isolation — each task runs on auto/{task-id}, main is never touched
• Three-layer safety — hooks block destructive ops, CLI caps turns, mission brief constrains scope
• Automatic PRs — completed tasks push branches and create PRs via gh

Plugin contents

Type	Name	Description
Command	/taskrunner	Run pending tasks from the queue
Command	/taskrunner-add	Add a task to the queue
Command	/taskrunner-list	Show queue status
Agent	task-executor	Debug and monitor autonomous execution
Safety	block-interactive.sh	Blocks AskUserQuestion in headless mode
Safety	safety-gate.sh	Blocks rm -rf, git push --force, DROP TABLE, deploys
Safety	syntax-check.sh	Advisory TypeScript error detection after edits

Design decisions

• Safety hooks live in safety/ (not hooks/) so they're only active during autonomous execution, not during interactive sessions
• Queue file defaults to project root (./queue.json), not plugin directory
• Uncommitted work is stashed before task execution and restored after
• Pre-snapshot diffing ensures only task-created files are auto-committed (not pre-existing dirty files)

Production origin

Extracted from AEGIS, a production autonomous AI agent that has executed 80+ tasks across 11 repositories. The safety architecture, branch lifecycle, and mission brief patterns were developed through real incidents — not theoretical design.

Standalone repo: Stackbilt-dev/cc-taskrunner

Test plan

• Install plugin via claude plugin:add
• Verify /taskrunner-add creates queue.json with correct task structure
• Verify /taskrunner-list displays queue status
• Verify /taskrunner --dry-run previews without executing
• Verify /taskrunner --max 1 executes a single task on isolated branch
• Verify safety hooks block AskUserQuestion and destructive commands during execution
• Verify stash/pop protects uncommitted work

🤖 Generated with Claude Code