pdb-env tests Git worktree alternative

pdb-env makes a compelling case that workspace isolation should be a filesystem primitive, not a side effect of version control. The tradeoff is blunt but honest: today’s correctness-first implementation spends disk to avoid hidden complexity.

• –Full-copy directories provide portable behavior, native file watchers, and an easy correctness baseline.
• –Separate mutable dependency graphs prevent repeated agents from sharing or corrupting node_modules state.
• –Experimental APFS clones could reduce startup time and physical disk growth, but silent fallback must be eliminated.
• –Git worktrees remain useful for branching, but they unnecessarily couple agent workspace mechanics to VCS state.
• –This is workspace isolation, not security containment; trusted agents still need containers or microVMs for hostile-code boundaries.