feat(editor): add WCMG (Combat Maneuver Group) open catalog format

Novel replacement for the hardcoded class-mutex tables
the WoW client uses to grey out incompatible action-bar
buttons. Each entry is one mutually-exclusive spell
group: Warrior stances (Battle/Defensive/Berserker),
Druid shapeshift forms (Bear/Cat/Travel/Tree/Moonkin),
Hunter aspects (Hawk/Cheetah/Pack/Viper/Dragonhawk/Beast/
Wild), DK presences (Frost/Unholy/Blood). The action-bar
update path uses the catalog to know which spells share
a mutex bucket and clear "currently active" outlines
when a sibling is cast.

Six categoryKind enum values (Stance / Form / Aspect /
Presence / Posture / Sigil) and variable-length members[]
array of spell IDs (refs WSPL). Three presets:
makeWarrior (Warrior 3-stance), makeDruid (5 shapeshift
+ 2 flight, separate buckets so flying isn't broken by
Cat Form), makeAllMutex (cross-class catalog with one
representative group per mutex-having class).

Validator catches several authoring bugs: empty members[]
(group has nothing to switch between), spellId 0,
duplicate spellId within a group, and — most usefully —
the same spellId appearing in two different exclusive
groups (which would make the action-bar mutex
undecidable: which group's outline does the bar use?).
Warns on single-member groups (mutex with one element
has no exclusion to enforce).

Format count 98 -> 99 (one short of triple-digit
milestone). CLI flag count 1112 -> 1117.

tools/editor/cli_arg_required.cpp

@@ -304,6 +304,8 @@ const char* const kArgRequired[] = {
     "--gen-scb", "--gen-scb-maintenance", "--gen-scb-helptips",
     "--info-wscb", "--validate-wscb",
     "--export-wscb-json", "--import-wscb-json",
+    "--gen-cmg", "--gen-cmg-druid", "--gen-cmg-all",
+    "--info-wcmg", "--validate-wcmg",
     "--gen-weather-temperate", "--gen-weather-arctic",
     "--gen-weather-desert", "--gen-weather-stormy",
     "--gen-zone-atmosphere",