Auto Setup

It checks that tools are actually installed before configuring them, which saves you from broken gate commands. Writes everything to `.claude/settings.json` and won't clobber existing config without asking first. The real win is not having to remember the right incantations for every language's toolchain. Works with monorepos too. Use it when you're joining a new codebase or spinning up a project and want quality gates running in two minutes instead of twenty.