Optional customization and upgrade tool. This skill should be used when the user says "initialize arness code", "arness code init", "arn-code-init", "init arness code", "setup arness code", "arness code setup", "set up arness code", "start arness code", "upgrade arness code", "update arness code", "configure arness code for this project", "add arness code to this project", "reconfigure arness code", "review arness config", "customize arness config", "arness settings", or wants to customize Arness configuration, review current settings, or upgrade after a plugin update. Handles both existing codebases (analyzes patterns) and greenfield projects (recommends patterns based on technology choices). Also handles upgrades after plugin updates.