Previously all player spell casts played ARCANE school sounds regardless
of the actual spell school. Now loadSpellNameCache() reads SchoolMask
(bitmask, TBC/WotLK) or SchoolEnum (Vanilla/Classic) from Spell.dbc and
stores it in SpellNameEntry. handleSpellStart/handleSpellGo look up the
spell's school and select the correct MagicSchool for cast sounds.
DBC field indices: WotLK SchoolMask=225 (verified), TBC=215, Classic/Turtle
SchoolEnum=1 (Vanilla enum 0-6 converted to bitmask).