Add Cloud design pilot skill

[Drixled]

Summary

• make Linear the canonical project plan and archive the local checklist
• add ADR 0011, deferring a standalone core skill until reuse is proven
• add the single Cloud pilot skill kilo-design-cloud with overlay, internal references, and primary-actions/tabs recipes
• update README, glossary, and prior ADRs to match the Cloud-pilot-first direction

Validation

• npx skills@latest add . --list --full-depth --yes finds exactly one skill: kilo-design-cloud
• git diff --check passed
• markdown whitespace check passed

Linear: VVV-132