fix: expansion-aware SpellRange.dbc loading and Classic spell tooltip fields

SpellRange.dbc layout fix:
- Classic 1.12 uses field 2 (MaxRange), TBC/WotLK use field 4 (MaxRangeHostile)
- Add SpellRange layout to each expansion's dbc_layouts.json
- Replace hardcoded field 5 with layout-driven lookup in SpellRange loading
- Corrects previously wrong range values in WotLK spellbook tooltips

Classic 1.12 Spell.dbc field additions:
- Add CastingTimeIndex=15, PowerType=28, ManaCost=29, RangeIndex=33 to
  classic/dbc_layouts.json so Classic spellbook shows mana cost, cast time,
  and range in tooltips

Trainer fieldCount guard:
- Lower Trainer::loadSpellNameCache() Spell.dbc fieldCount threshold from
  154 to 148 so Classic trainers correctly resolve spell names from Spell.dbc

Data/expansions/wotlk/dbc_layouts.json

@@ -4,6 +4,7 @@
     "Name": 136, "Tooltip": 139, "Rank": 153, "SchoolMask": 225,
     "PowerType": 14, "ManaCost": 39, "CastingTimeIndex": 47, "RangeIndex": 49
   },
+  "SpellRange": { "MaxRange": 4 },
   "ItemDisplayInfo": {
     "ID": 0, "LeftModel": 1, "LeftModelTexture": 3,
     "InventoryIcon": 5, "GeosetGroup1": 7, "GeosetGroup3": 9,