The path limits are settled: leave them, and say what they are

Measured rather than adjusted. The longest path on a full install is 21
characters against a native cap of about 117, so neither that nor
SplitDisk's 512 binds anything, and both can be raised if that ever
changes. Looking for the evidence turned up the limit that did bind - the
prompt's 127 bytes, fixed in the commit before this one.

NOTES.md

@@ -2,17 +2,6 @@
 
 Temporary notes from the SBFS v2 and CosmOS review, in priority order.
 
-## Establish one portable path-length limit
-
-SplitDisk carries paths up to 511 characters, while the native path machinery appears to
-use a 255-byte limit. Paths are not stored on disk, so this does not change the format, but
-the host can construct a tree addressable by a path that CosmOS cannot express in one
-operation.
-
-Declare a portable CosmOS/SBFS path limit and have SplitDisk enforce it when modifying an
-image. The native 255-byte limit is reasonable; the important property is agreement and
-documentation. Component names remain limited to 22 bytes independently.
-
 ## Bound the number of directory entries
 
 The parent field is 16 bits and stores `descriptor index + 1`, with zero reserved for the