Final validation: Init dev env

Summarised from verification.md. The issue has no formal acceptance criteria, so each bullet of the issue body is used as one.

Final validation evidence

Acceptance criterion (issue body)	How it was proved	Where
Add CLAUDE.md, AGENTS.md	Both files added; CLAUDE.md imports AGENTS.md	CLAUDE.md, AGENTS.md
Add .claude/settings.json using the-loop's as reference	Byte-identical to the reference file	verification.md
Add the-loop: a .the-loop folder and the Claude plugin	.the-loop/ exists; the settings register the marketplace and enable the-loop@the-loop	verification.md
Run the-loop's init: sets up docs/	docs/{specs,capabilities,architecture,decisions,learnings} exist with their indexes	verification.md
No CLI setup; exactly 3 files under .the-loop	ls -A .the-loop shows only the three files; no cli-config.yaml	verification.md