New extras service: installs the Claude Code CLI, creates separate
work/personal CLAUDE_CONFIG_DIR accounts behind claude-work/claude-personal
aliases, and applies settings.json defaults to both (model=claude-sonnet-5,
effortLevel=medium, ENABLE_PROMPT_CACHING_1H=1). A shared ~/.claude-shared/
CLAUDE.md holds the durable personal conventions (modular/reuse code,
numbered CLI menus with 0=exit, Playwright verification for UI changes)
and both accounts pull it in via @import so there's one copy to maintain.
Login itself (browser OAuth) can't be scripted - this only prepares the
directories/aliases/config; each account still needs one interactive
login. Tested fresh-install, rerun/cancel detection, and the jq settings
merge (preserves hand-added keys) in a scratch HOME.
