Update README: manual Homebrew, add xAI/Z.AI/Copilot keys, fix PostArgs

Add note to ignore Homebrew Next steps - template handles PATH

Update Overview: add OpenClaw repo link, API key requirement, fix Homebrew formatting

Fix Overview text justification - shorten Homebrew instructions

Add Z.AI API key support

Make Homebrew optional, add xAI/Grok support

docs: Update README with -s config check

fix: Use -s instead of -f for config check (catches empty files)

chore: Remove unnecessary .gitignore

chore: Remove redundant default-config folder

feat: Update docker-compose with Homebrew support

docs: Add Table of Contents and simplify pre-CA install

docs: Add Homebrew & Skills documentation

Delete SYNC-TO-CA.md

docs: Add CA sync workflow documentation