Sync Skills from obra/superpowers

Periodic upstream sync: check https://github.com/obra/superpowers for new or changed skills, classify each against tunan's existing coverage, identify complementary patterns worth absorbing, and either create new tunan skills or enhance existing ones with the absorbed techniques. Run this on a recurring cadence — superpowers evolves rapidly (v6.1.1 at time of authoring) and its TDD-first, systematic-debugging, and subagent-driven-development patterns are designed to complement tunan's engineering pipeline.

What superpowers brings

superpowers is a "complete software development methodology for coding agents" built by Jesse Vincent / Prime Radiant. Its skills enforce a strict workflow: brainstorming → worktree isolation → plan writing → subagent-driven execution with two-stage review → verification → branch completion. Key design traits that differ from tunan:

• Mandatory gate enforcement. Every skill has <HARD-GATE> blocks that forbid skipping phases. The using-superpowers bootstrap skill enforces skill invocation before ANY agent response — even clarifying questions.
• TDD as law, not guidance. "Code written before tests → delete it. Start over." No exceptions. The RED-GREEN-REFACTOR cycle is presented as an iron law, not a preference.
• Anti-rationalization tables. Skills include explicit "Red Flags — STOP" tables listing the exact rationalizations agents use to bypass process, with rebuttals. This is a meta-cognitive defense pattern tunan doesn't use.
• Two-stage subagent review. subagent-driven-development runs a spec-compliance reviewer THEN a code-quality reviewer after every task — two independent gates, not one combined review.
• Zero-context plan writing. Plans are written "assuming the engineer has zero context for our codebase and questionable taste" — every task includes exact file paths, complete code, and verification steps.
• Session-start hook injection. A SessionStart hook injects the using-superpowers bootstrap into every session, ensuring skills are mandatory from message one.

Core Loop