Stabilize Homebrew install-from-HEAD validation

[mdheller]

Summary

TurtleTerm PR #3 currently has Homebrew Validation red in every matrix cell at Install TurtleTerm formula from HEAD.

Current confirmed state on PR #3 head 06390c6202b8e9b708d102e3e1ab5eb7275b95aa:

Green:

• Homebrew formula audit

Still red:

• install from HEAD on macOS and Ubuntu matrix jobs

Why this likely needs focused remediation

The formula metadata/audit surface passes. The failure is in install/build execution, likely around build/runtime dependency behavior or helper-script invocation during formula install.

Acceptance criteria

• Capture exact Homebrew install failure excerpt.
• Fix formula install path or builder invocation so brew install --HEAD succeeds on supported matrix jobs.
• Formula test and CLI smoke test run after install.

Related

• PR docs: add CloudShell FOG integration profile (draft) #3: CloudShell FOG integration profile and CI remediation sweep.