feat(editor): add WSKP (Sky Parameters) — 119th open format

Novel replacement for the LightParams.dbc + Light.dbc
pair vanilla WoW used to drive the per-zone diurnal sky
cycle. Each entry binds one (mapId, areaId,
timeOfDayHour) triplet to its sky-rendering parameters:
sky-dome zenith and horizon colors, sun angle and color,
fog start/end distances, cloud-layer opacity, and cloud
drift speed in tenths-mph.

The renderer interpolates between adjacent keyframes
when the in-game clock crosses an hour boundary, so a
4-keyframe set (Dawn/Noon/Dusk/Midnight) produces the
full diurnal cycle through linear interpolation. Servers
can author finer-grained keyframes (e.g. every 3 hours)
for smoother transitions.

Three preset emitters demonstrating the catalog's range:
makeStormwindDay (4 standard temperate keyframes from
lavender dawn through bright noon to deep blue-black
midnight), makeNorthrendArctic (4 cold steel-blue
keyframes with high-density ice fog peaking at the
midnight blizzard whiteout — minimum 30yd visibility),
makeOutlandHellfire (3 keyframes — no midnight, since
Outland's permanent gravitational anomaly from the
Twisting Nether keeps the sky lit; iconic crimson +
orange palette throughout).

Validator's most novel checks: per-(mapId, areaId,
timeOfDayHour) triple uniqueness — two keyframes at the
same hour for the same area would render in unstable
order during diurnal interpolation. Plus
fogStartYards >= fogEndYards (inverted falloff) error,
sunAngleDeg outside [0,360] warning (renderer wraps
modulo but suggests authoring confusion).

Format count 118 -> 119. CLI flag count 1255 -> 1260.

tools/editor/cli_arg_required.cpp

@@ -365,6 +365,8 @@ const char* const kArgRequired[] = {
     "--gen-lma", "--gen-lma-raid", "--gen-lma-afk",
     "--info-wlma", "--validate-wlma",
     "--export-wlma-json", "--import-wlma-json",
+    "--gen-skp", "--gen-skp-arctic", "--gen-skp-hellfire",
+    "--info-wskp", "--validate-wskp",
     "--gen-weather-temperate", "--gen-weather-arctic",
     "--gen-weather-desert", "--gen-weather-stormy",
     "--gen-zone-atmosphere",