docs: update endpoint follow-up tracking

Update TODO.md after the recently enabled synchronization and extended volume
information endpoints.

The file/logical-record/physical-record synchronization entries no longer need
to list NCP 0x04, 0x0c, and 0x1f as disabled or dummy endpoints. Keep the
remaining work focused on requester/NWTESTS coverage plus timeout and
error-code verification for set-oriented locking calls.

Also track follow-up work for fields that are currently returned as zero by
Get Extended Volume Information because MARS-NWE does not yet model them. The
endpoint now returns the documented NWVolExtendedInfo reply, but NetWare-
specific counters such as suballocation, deleted-file/limbo, compression,
migration, EA, Directory Services, and timestamp fields should only be filled
once reliable backing filesystem or MARS-NWE metadata is available.

This is documentation-only and does not change NCP behavior.

TODO.md

@@ -109,12 +109,32 @@ Follow-up:
 - Verify the implemented file/logical-record/physical-record calls against the
   Novell SDK request/reply layouts and a real DOS requester or direct test
   caller.
-- Implement or explicitly decide the fate of `NCP 0x04 Lock File Set`, which
-  is currently present only as a disabled `#if 0` endpoint.
-- Enable and test `NCP 0x0c Release Logical Record`; the existing code path can
-  distinguish release from clear, but the case label is currently disabled.
-- Replace the `NCP 0x1f Clear Physical Record Set` dummy/no-op with real
-  physical-record-set cleanup, or document why no supported client relies on it.
+- Continue direct requester or NWTESTS coverage for the file, logical-record,
+  and physical-record synchronization calls that are now wired.
+- Verify timeout and error-code behavior for set-oriented locking calls against
+  a real requester, especially where MARS-NWE currently relies on the existing
+  underlying share implementation.
+
+### Extended volume information field mapping
+
+Current status:
+
+- `NCP 0x16/0x33 Get Extended Volume Information` returns the documented
+  `NWVolExtendedInfo` reply and fills the core fields that can be derived from
+  generic Unix filesystem statistics.
+- NetWare-specific fields that MARS-NWE does not currently model are returned
+  as zero for now instead of guessed values.
+
+Follow-up:
+
+- Fill additional `NWVolExtendedInfo` fields when reliable data is available
+  from the backing filesystem or from MARS-NWE metadata.
+- Candidate fields include suballocation, deleted-file/limbo accounting,
+  compression counters, migration counters, EA counters, Directory Services
+  object id, and last-modified timestamp data.
+- Treat compression-related fields as real follow-up work rather than permanent
+  zeroes; populate them only when the backing filesystem exposes trustworthy
+  compressed-file or compressed-block accounting.
 
 ## Printing / Queue backend