Files copied from the nix store inherit read-only permissions, causing
subsequent home-manager activations to fail with "Permission denied".
Add rm -f before copy and chmod u+w after copy for all plugin files:
- humanlayer commands and agents
- local commands and skills
- micro-skills
- beads formulas
Executed-By: nixos_configs/crew/hermione
Rig: nixos_configs
Role: crew
John Ogle
c2d286087f