chore: archive completed plans and specs

[rogerdigital]

Summary

Post-1.0.0 housekeeping:

• Moves the 31 completed implementation plans and 21 completed designs from docs/superpowers/{plans,specs} to docs/archive/superpowers/{plans,specs}, following the existing docs/archive/ convention (git mv, history preserved). Every plan in the set has shipped — through the 0.5–0.8 series and 1.0.0 — and the durable release evidence lives in docs/validation/1.0.0-readiness.md.
• Fixes the one real cross-directory relative link (community-first-interface.md → docs/cli.md) for the new depth; intra-set relative links move together and stay valid.
• Removes local .DS_Store files (untracked, already gitignored).
• Merged remote branches docs/a2-execution-note and fix/tag-hierarchy-exemption deleted server-side (both verified merged into main before deletion).

Active docs tree is now: README.md, AGENTS.md/CLAUDE.md, docs/cli.md, docs/images, docs/validation, tasks/lessons.md, skills/.

Validation

• Full gate: lint, obsidian lint, build, tests — 976 pass (documentation move only; no code touched).