feat(editor): add WLAN (Localization) — 123rd open format

Novel replacement for the per-language overlay tables
vanilla WoW carried as Locale_*.MPQ patches plus the
Spell.dbc / Item.dbc trailing 16-locale string columns.
Each entry binds one (originalKey, languageCode,
namespace) triple to its localized translation,
forming a per-language overlay applied AFTER any
per-format catalog has resolved its primary text.

Eleven languageCode values cover the canonical WoW
locales (enUS / enGB / deDE / esES / frFR / itIT /
koKR / ptBR / ruRU / zhCN / zhTW) plus Unknown=255 as
escape hatch. Eight namespace values segment the
lookup space (UI / Quest / Item / Spell / Creature /
Tooltip / Gossip / System) so a UI button "Cancel"
doesn't collide with an item description containing
the word "Cancel".

UTF-8 multibyte support is the novel demonstration —
the originalKey field is typically ASCII (English
canonical key), but localizedText holds Korean (취소),
Simplified Chinese (取消), or other non-Latin scripts.
The string-length-prefixed binary serialization
preserves byte-identical round-trip regardless of
encoding.

Three preset emitters: makeUIBasics (5 UI translations
of the "Cancel" button across deDE/frFR/esES/koKR/zhCN
including the Korean and Chinese multibyte UTF-8 strings),
makeQuestSample (3 entries — one quest title in
deDE/frFR/koKR illustrating the dotted-key convention
"QUEST.123.title"), makeTooltipSet (4 item-tooltip
strings in deDE+frFR — the high-volume client
localization use case).

Validator's most novel check is per-(originalKey,
languageCode, namespace) triple uniqueness — two
entries with all three matching would tie at runtime
when the locale-aware text layer looks up an override.
Plus the warning on empty localizedText (the override
would render blank — possibly worse than fallback to
the catalog default).

Format count 122 -> 123. CLI flag count 1283 -> 1288.

tools/editor/cli_arg_required.cpp

@@ -377,6 +377,8 @@ const char* const kArgRequired[] = {
     "--gen-prg", "--gen-prg-horde", "--gen-prg-high",
     "--info-wprg", "--validate-wprg",
     "--export-wprg-json", "--import-wprg-json",
+    "--gen-lan", "--gen-lan-quest", "--gen-lan-tooltip",
+    "--info-wlan", "--validate-wlan",
     "--gen-weather-temperate", "--gen-weather-arctic",
     "--gen-weather-desert", "--gen-weather-stormy",
     "--gen-zone-atmosphere",