dedup shot-haste loops behind libcast.ApplyShotHaste

The three customcast handlers (Aimed Shot, Multi-Shot, Steady Shot) each
iterated 1..32 UnitBuff slots checking the same four icon paths for
haste-providing buffs. Lifted into libcast.ApplyShotHaste which iterates
the populated auras once via C_UnitAuras.GetUnitAuras and reads from a
single SHOT_HASTE lookup table. Three loop copies collapse to one helper.

Kept texture-keyed matching (rather than spellID) because the Naxx
trinket and Quick Shots procs have spell-ID variants across server
flavors but stable icons.

modules/turtle-wow.lua

@@ -331,24 +331,7 @@ pfUI:RegisterModule("turtle-wow", "vanilla", function ()
     libcast.customcast[strlower(trueshot)] = function(begin, duration)
       if begin then
         -- cast time is 1sec, however it takes 1.4sec to fire in average
-        local duration = duration or 1400
-
-        for i=1,32 do
-          if UnitBuff("player", i) == "Interface\\Icons\\Racial_Troll_Berserk" then
-            local berserk = 0.3
-            if((UnitHealth("player")/UnitHealthMax("player")) >= 0.40) then
-              berserk = (1.30 - (UnitHealth("player") / UnitHealthMax("player"))) / 3
-            end
-
-            duration = duration / (1 + berserk)
-          elseif UnitBuff("player", i) == "Interface\\Icons\\Ability_Hunter_RunningShot" then
-            duration = duration / 1.4
-          elseif UnitBuff("player", i) == "Interface\\Icons\\Ability_Warrior_InnerRage" then
-            duration = duration / 1.3
-          elseif UnitBuff("player", i) == "Interface\\Icons\\Inv_Trinket_Naxxramas04" then
-            duration = duration / 1.2
-          end
-        end
+        local duration = libcast.ApplyShotHaste(duration or 1400)
 
         local _,_, lag = GetNetStats()
         local start = GetTime() + lag/1000