Fix AI Organize CLI discovery in desktop app

[ajia1206]

Summary

• Fix AI Organize CLI discovery when FanBox is launched as a macOS desktop app.
• Add common user CLI locations, including ~/.local/bin, Homebrew, and nvm Node bins, before shell-based lookup.
• Return an absolute, shell-quoted agent command so the embedded terminal does not depend on its own PATH.

Root Cause

FanBox launched from the GUI does not inherit the user's interactive terminal PATH. The existing zsh -lc "command -v claude" check could miss CLIs installed under user-managed paths even though they worked in Terminal.

Validation

• node --check server.js
• git diff --check origin/master...HEAD
• npm run check:vendor-patch
• Started server.js with env -i and minimal PATH on FANBOX_PORT=5567
• curl /api/organize/launch returned ok:true with '/Users/getui/.local/bin/claude' ...