Clarify and support Homebrew-installed workspace discovery

[codeforester]

Problem

Base now supports installation through the Homebrew tap. In that mode, Homebrew places Base under its Cellar and stable opt prefix, for example /opt/homebrew/opt/base/libexec, and the formula rewrites basectl/base-wrapper so BASE_HOME points there.

That works for Base runtime lookup, but it changes the original workspace assumption: project repositories were expected to sit next to the base checkout, and basectl projects list defaults to scanning BASE_HOME�s parent. For a Brew install, that default becomes a Homebrew directory rather than the developer workspace such as ~/work.

Desired outcome

• Keep Brew-installed Base as a supported first-class layout.
• Add a durable user/workspace config for the workspace root, likely defaulting to ~/work during onboarding or setup.
• Teach project discovery commands to prefer the configured workspace root before falling back to BASE_HOME�s parent.
• Document the difference between Git-checkout installs and Homebrew installs.
• Ensure basectl update messaging points Brew users to brew upgrade codeforester/base/base rather than Git update behavior.

Related immediate packaging fix

The Homebrew formula should also stop installing moving master while labeling the package 0.1.0; it should point at the v0.1.0 release tag or a release artifact.

[codeforester]

Opened the immediate tap packaging PR: codeforester/homebrew-base#1

That PR fixes the release-source problem by pinning the stable Homebrew formula to the v0.1.0 archive plus SHA256. The broader workspace-root behavior for Brew-installed Base remains tracked here.