Support host filesystem paths containing commas

[huzaifa-d]

Allow valid host paths containing commas to be passed through NVX's mount interface. The current comma-separated syntax treats part of the path as another argument and rejects it.

Example	Expected behaviour
Mount C:\projects\alpha,beta read-write	Expose that exact directory and allow writes.
Mount C:\reports\2026, final read-only	Expose that exact directory and block writes.
Deny a subdirectory inside either export	Keep the denied subdirectory inaccessible.

Provide an unambiguous way to encode these paths without changing the meaning of existing mount arguments.

Verify the exact directory is mounted and that its requested permissions are preserved.

MXC schema requirement: filesystem.readonlyPaths and filesystem.readwritePaths accept path strings without excluding commas.