Breaking: auto_install_agent_deps() is now disabled by default. Set HERMES_WEBUI_AUTO_INSTALL=1 to re-enable. New _trusted_agent_dir() checks ownership and permission bits. Addresses #842 by @tomaioo.
* feat: auto-install missing agent deps on startup
* fix: patch HERMES_HOME in test_skips_when_agent_dir_missing to prevent real agent fallback
The test patched HERMES_WEBUI_AGENT_DIR to a nonexistent path but left
HERMES_HOME unpatched. In the full test suite HERMES_HOME resolves to the
real hermes agent dir, causing the fallback in _agent_dir() to find and
use it — making auto_install_agent_deps() call pip instead of returning
False. Fix: also patch HERMES_HOME to a nonexistent dir in env_overrides.
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Co-authored-by: Nathan Esquenazi <nesquena@gmail.com>
