Volume browser paths are API paths, not native filesystem paths. They
need stable slash-separated encoding so paths containing spaces,
backslashes, or percent-encoded characters can round-trip between the
browser and the agent without escaping the mounted volume root.
This adds a small codec at the volume-host boundary, verifies
symlink/root containment on the resolved native path, and keeps the
local file browser from normalizing user-facing request.
f646bc4f92