fix(mount): stop double-applying umask in Mkdir (#9063)

Mkdir was masking in.Mode with wfs.option.Umask on top of the kernel's
VFS umask pass, so a caller with umask=0 who requested mkdir(0777) got
0755 (0777 & ~022). Create and Symlink don't apply this second pass —
Mkdir was the odd one out. The resulting dirs had fewer write bits than
the caller asked for, which broke cross-user rename permission checks
(kernel may_delete rejects with EACCES when the parent lacks o+w even
though the caller explicitly requested it) and blocked pjdfstest
tests/rename/21.t and its cascading checks.

Drop the extra umask so Mkdir trusts in.Mode exactly like Create. The
CLI -umask flag still covers the internal cache dirs that the mount
creates for itself via os.MkdirAll; only the user-facing Mkdir path
changes.

Unblocks tests/rename/21.t — full pjdfstest suite is now 236 files /
8819 tests, all PASS, and known_failures.txt is empty.

test/pjdfstest/known_failures.txt

@@ -6,8 +6,3 @@
 # A failure in any test NOT listed here will cause the CI job to fail,
 # catching regressions immediately.
 
-# ── Directory rename permission edge case ──────────────────────────────
-# Cross-directory rename of a subdirectory with restricted permissions
-# causes cascading test failures within the test file.
-tests/rename/21.t
-

weed/mount/weedfs_dir_mkrm.go

@@ -38,7 +38,7 @@ func (wfs *WFS) Mkdir(cancel <-chan struct{}, in *fuse.MkdirIn, name string, out
 			Mtime:    now,
 			Crtime:   now,
 			Ctime:    now,
-			FileMode: uint32(os.ModeDir) | in.Mode&^uint32(wfs.option.Umask),
+			FileMode: uint32(os.ModeDir) | in.Mode,
 			Uid:      in.Uid,
 			Gid:      in.Gid,
 		},