feat: add /qa-cli skill for CLI tools, servers, and headless projects

[StressTestor]

summary

adds /qa-cli — a QA skill for projects that don't have a web UI. CLI tools, API servers, libraries, background services.

the existing /qa and /qa-only skills are browser-based (they use the browse binary to navigate URLs, take screenshots, click elements). but a lot of projects are headless — CLIs, servers, libraries. those need a different QA approach: run the test suite, exercise the real binary with smoke tests, hit server endpoints, and report what's passing, what's broken, and what's untested.

what it does

9 phases:

1. discovery — detect project type (node/rust/python/go), find test commands, build commands, CLI entry points, server entry points
2. build — build the project. if it doesn't build, diagnose and fix before testing
3. test suite — run existing tests, parse results, categorize failures (bug/flaky/stale)
4. CLI smoke tests — exercise every subcommand with --help, run happy-path commands with safe read-only args, test error handling (bad inputs should produce clean messages, not stack traces)
5. server smoke tests — start server, hit health endpoint, exercise documented routes, stop server
6. coverage gap analysis — compare source modules vs test files, flag untested critical paths
7. report — structured output with health score (0-100), tables for each phase
8. fix loop — for each failure, diagnose root cause, make minimal fix, atomic commit, re-test
9. before/after summary — health score delta, fixes applied, remaining issues, ship readiness

tested on

ran it manually against StressTestor/pr-prism (v2.0.0, TypeScript CLI + server, 199 tests). it found a real bug: prism scan --repo invalid produced a raw stack trace instead of a clean error message. fixed it in the same session.

changes

• qa-cli/SKILL.md.tmpl — new skill template (9 phases, ~300 lines of prompt)
• qa-cli/SKILL.md — generated output
• SKILL.md.tmpl — added qa-cli to proactive suggestion list
• SKILL.md — regenerated
• scripts/gen-skill-docs.ts — added qa-cli to findTemplates()

test plan

• bun test passes (static validation picks up the new skill)
• bun run gen:skill-docs --dry-run passes (generated SKILL.md matches committed)
• manual test: ran the full qa-cli workflow against a real project, found and fixed a bug