Problem: browser-based UI validation in this repo became fragile from a Codex git worktree even when the UI change itself was small.
Root cause: worktree git metadata, missing runtime dependencies in the worktree, and browser blocking of file:// previews created verification friction unrelated to the code.
Keep doing: if browser testing gets sticky, switch to a normal branch checkout and serve previews over localhost.
Avoid: spending hackathon time debugging worktree-specific UI testing failures or relying on file:// preview URLs.