Third report of gateway crashing with:
ImportError: cannot import name 'get_hermes_home' from 'hermes_constants'
Root cause: stale .pyc bytecode files survive code updates. When Python
loads a cached .pyc that references names from the old source, the import
fails and the gateway won't start.
Two bugs fixed:
1. Git update path: no cache clearing at all after git pull
2. ZIP update path: __pycache__ was explicitly in the preserve set
Added _clear_bytecode_cache() helper that removes all __pycache__ dirs
under PROJECT_ROOT (skipping venv/node_modules/.git/.worktrees). Called
in both git and ZIP update paths, before pip install.
c4cf20f564