Use ClassicAPI UnitPower* for power reads; drop GetUnitField/SuperWoW paths

Add ClassicAPI UnitPower/UnitPowerMax/UnitPowerMissing/UnitPowerType wrappers
and route the power conditionals through them:
- ValidatePower/ValidateRawPower/GetCachedPlayerPower(Percent) use UnitPower /
  UnitPowerMax (omitted type = primary power, matching the old UnitMana path).
- ValidatePowerLost uses UnitPowerMissing (one call vs max - current).
- powertype/nopowertype use ClassicAPI.UnitPowerType.

Replace the SuperWoW "2nd return of UnitMana = caster mana" druid hack in
ValidateDruidRawMana and the #showtooltip OOM check with UnitPower(unit, 0),
which reads the mana slot directly and survives shapeshift. Verified in Cat
Form: UnitPower('player', 0) returns caster mana while UnitPower('player', 3)
returns energy.

Remove the now-dead Nampower GetUnitField-based GetUnitPower/GetUnitMaxPower
wrappers and POWER_FIELDS tables (no caller passed a powerType, so that path
never ran).

Core.lua

@@ -947,13 +947,14 @@ function CleveRoids.TestForActiveAction(actions)
                 -- Prefer IsSpellUsable result if available (Nampower)
                 actions.active.oom = (notEnoughPower == 1)
             else
-                -- SuperWoW: UnitMana returns (current power, caster mana) for druids
-                local currentPower, casterMana = UnitMana("player")
-
-                -- For druids with SuperWoW, use caster mana for spell cost checks
-                local manaToCheck = currentPower
-                if CleveRoids.playerClass == "DRUID" and type(casterMana) == "number" then
-                    manaToCheck = casterMana
+                -- Read caster mana directly for druids (the mana slot survives
+                -- shapeshift, 0 = Enum.PowerType.Mana); other classes use their
+                -- primary power. Replaces the SuperWoW UnitMana 2nd-return hack.
+                local manaToCheck
+                if CleveRoids.playerClass == "DRUID" then
+                    manaToCheck = CleveRoids.ClassicAPI.UnitPower("player", 0)
+                else
+                    manaToCheck = CleveRoids.ClassicAPI.UnitPower("player")
                 end
 
                 actions.active.oom = (manaToCheck < actions.active.spell.cost)