docs: sharpen software-development skills

[whoislikemiha]

Summary

• expand systematic-debugging with a tighter feedback-loop discipline, minimization step, ranked falsifiable hypotheses, and debug-log cleanup guidance
• add vertical tracer-bullet guidance to test-driven-development to avoid horizontal test/code batches
• add skill-writing quality principles to hermes-agent-skill-authoring: predictability, context load, completion criteria, leading words, no-op pruning, and common failure modes

Test Plan

• Validated SKILL.md frontmatter with the repo venv + PyYAML
• Ran git diff --check
• Synced bundled skills locally with ./venv/bin/python tools/skills_sync.py

[teknium1]

Merged via PR #49944 (docs salvage cluster 2). Your commit was cherry-picked onto current main with your authorship preserved in git log — rebase-merged so it lands under your name. Thanks for the contribution!