Align rename permission checks with NetWare trustee semantics. A same-directory
rename should be controlled by the Modify right instead of requiring a broader
R/W/M combination. For moves to another parent directory, require Create rights
on the destination parent.
Also invalidate the trustee rights cache after adding or deleting trustee
assignments so newly granted rights are visible immediately to subsequent
operations.
This fixes the MARIO trustee test where rename failed with R/W/M/F and even
R/W/C/E/M/F, while the same operation succeeded only with the broader all-rights
set.
