- install.sh: detects shell profile (zsh/bash/profile), adds PATH entry if missing
- install.ps1: adds to User PATH via SetEnvironmentVariable if missing
- Both are idempotent — show "already in PATH ✓" on re-run
- mosaic/mosaic.ps1: accept "help" and "version" as bare subcommands
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>