feat: add lightweight workflow paths

[MageByte-Zero]

Summary

Introduces a lightweight four-path workflow so small, low-risk work no longer pays the full planning and review cost.

• Adds quick for bounded low-risk code work and direct incident hotfix acceptance.
• Keeps tweak lightweight and preserves legacy Hotfix and Full contract/approval/plan/review controls.
• Requires bounded verification plus test_result: pass for short paths; direct Hotfix also proves the original symptom regression.
• Adds an auditable escalation path from Quick, direct Hotfix, or Tweak to Full when risk or scope grows.
• Aligns CLI guards, skills, docs, and all generated installer phase guards.

Why

Simple requests were forced through the full exploration, specification, contract, execution-plan, and review path. This added visible latency and token cost without providing proportional safety.

Validation

• npm run build
• npm test
• node scripts/validate-artifacts docs/examples/add-dark-mode
• node scripts/validate-artifacts docs/examples/refactor-auth-boundary
• Independent SDD reviews for recommendation, guards, skills, distribution, and regression