graphify install --platform hermes always wrote the skill to ~/.hermes/skills,
the POSIX path. On Windows, Hermes scans %LOCALAPPDATA%\hermes\skills, so the
installed skill was never discovered. _platform_skill_destination now has a
hermes branch: Windows -> %LOCALAPPDATA%\hermes\skills, other OSes unchanged
(~/.hermes/skills). Pure path logic — no skillgen regeneration.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>