refactor(controller,xceadmin): drop generic Resource.unit, hardcode bytes for maxmem

Simplification per review feedback on e3b3ffa: a generic schema-driven
unit field touched the capnp wire schema (2 structs), C structs
(xce_resource_t/xce_resval_t), resobj.c's deep-copy/destroy, opget.c's
reply-build lookup, resources.yaml/resources.schema.json, and mapping.py
-- real cross-cutting cost for a mechanism only one resource (maxmem)
actually needs today.

Reverted all of that. The controller CLI (test.c) now just knows
"maxmem" is bytes-valued via a small explicit is_bytes_valued_resource()
name list, and adaptively picks the best-fit human unit at display time
(format_bytes_human, unchanged) -- same observable behavior (resval/
workerlist render maxmem as e.g. "30.90 GB"), zero wire schema surface.
Regenerated the xceadmin golden fixture back to its pre-unit-field size
(5304 bytes, exactly matching the size right after the mxj-only fix,
confirming a clean, complete removal).

Verified: 1095/1095 controller_unit_test (3 runs; one hit the
pre-existing flaky segfault already logged as bug-1553, unrelated),
228/228 xceadmin pytest, clean rebuild of lib/controller/xceadmin/xce_test.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/xceadmin/src/xcecommon/mapping.py

@@ -71,11 +71,7 @@ reason -- never a silent drop.
     runtime (e.g. ``scheduler.c`` copies these three fields straight out
     of the parsed resource). See :data:`_RESOURCE_VALTYPE`,
     :data:`_RESOURCE_ORDTYPE`, and the flag constants below for the exact
-    values. ``unit`` is mapped straight through from YAML when present --
-    a display-only hint (e.g. ``"bytes"``) the controller CLI (``resval``/
-    ``workerlist``) uses to render a human-readable value; the stored
-    value itself is never converted, only its display. ``idx`` and
-    ``lastReport`` remain unset: ``idx`` has no YAML source at all
+    values. ``idx`` and ``lastReport`` remain unset: ``idx`` has no YAML source at all
     (controller/runtime-assigned), and ``lastReport`` is a runtime
     timestamp field (epoch seconds of last report) -- excluded by
     Requirement 9.2's "no timestamp" rule. ``resourcemap`` has no
@@ -328,8 +324,6 @@ def _build_resource(item: dict, target: "capnp._DynamicStructBuilder") -> None:
     if item.get("release"):
         flags |= _RESOURCE_FLAG_RELEASE
     target.flags = flags
-    if "unit" in item:
-        target.unit = item["unit"]
 
 
 def _build_queue(item: dict, target: "capnp._DynamicStructBuilder") -> None:

src/xceadmin/tests/test_mapping.py

@@ -173,20 +173,6 @@ def test_map_list_section_noop_on_empty_or_missing_items(cluster_config):
     assert len(cluster_config.resources) == 0
 
 
-def test_map_list_section_resources_maps_unit_when_present(cluster_config):
-    items = [
-        {"name": "maxmem", "type": "numeric", "unit": "bytes"},
-        {"name": "maxcpus", "type": "numeric"},
-    ]
-    mapping.map_list_section(_spec_for("resources"), items, cluster_config)
-
-    r0, r1 = cluster_config.resources
-    assert r0.unit == "bytes"
-    # Every existing resource has no "unit" key -- must stay unset (empty
-    # Text default), not silently inherit or default to any value.
-    assert r1.unit == ""
-
-
 # ---------------------------------------------------------------------------
 # map_list_section: users.yaml/hosts.yaml -> ugroups/hgroups (named groups)
 # ---------------------------------------------------------------------------