Add 4 intern productivity skills: Engineering Journal, Code Explainer, Question Formatter, 1:1 Prep

[Hazey000]

Summary

• Adds 4 intern productivity skills: Engineering Journal (combined debug journal + learning log), Code Explainer / Onboarding, Question Formatter (with XY Problem guard), and 1:1 Prep
• The 4 skills are cross-linked — Engineering Journal feeds into 1:1 Prep, Question Formatter links to Journal for follow-up, and Code Explainer connects to both
• Updated INDEX.md with an Intern Productivity section

What's included

Skill	Path	Description
Engineering Journal	engineering-journal/SKILL.md	Debug sessions, learnings, and end-of-day reflections in weekly journal files
Code Explainer	code-explainer/SKILL.md	Explains code at file/directory/repo scope with 4 depth modes
Question Formatter	question-formatter/SKILL.md	Turns vague problems into structured questions for Slack, GitHub, or verbal
1:1 Prep	one-on-one-prep/SKILL.md	Prepares 1:1 meeting notes with auto-pulled activity and guided reflection

Test plan

• Verify each SKILL.md loads correctly as a Cursor skill (copy to .cursor/skills/ and invoke)
• Confirm cross-skill links work (e.g. Engineering Journal → 1:1 Prep integration)
• Check INDEX.md and README render correctly on GitHub