read spell rank via C_Spell.GetSpellSubtext

The rank string comes from the spell subtext ("Rank N"), which ClassicAPI's
C_Spell.GetSpellSubtext returns directly -- so drop nampower's
GetSpellRecField(spellId, "rank") here. The existing "Rank " gsub parse is
unchanged.

libs/libdebuff.lua

@@ -1125,7 +1125,7 @@ if hasNampower then
       
       -- Rank aus spellId ermitteln
       local rankNum = 0
-      local rankString = GetSpellRecField(spellId, "rank")
+      local rankString = C_Spell.GetSpellSubtext(spellId)
       if rankString and rankString ~= "" then
         rankNum = tonumber((string.gsub(rankString, "Rank ", ""))) or 0
       end

libs/libpredict.lua

@@ -291,7 +291,7 @@ pfUI.libdebuff_spell_start_other_hooks["libpredict"] = function(spellId, casterG
   local targetName = resolveNameFromGuid(targetGuid)
   if not targetName then return end
 
-  local rankStr = GetSpellRecField and GetSpellRecField(spellId, "rank") or ""
+  local rankStr = C_Spell.GetSpellSubtext(spellId) or ""
   local spellKey = spellName .. (rankStr or "")
 
   local amount = foreignCache[casterName] and foreignCache[casterName][spellKey]
@@ -355,11 +355,9 @@ pfUI.libdebuff_spell_go_hooks["libpredict"] = function(spellId, a1, a2, a3, a4,
       elseif hotType == "Renew" then duration = renewDuration or 15
       end
       local rank = 0
-      if GetSpellRecField then
-        local rankStr = GetSpellRecField(spellId, "rank")
-        if rankStr and rankStr ~= "" then
-          rank = tonumber((string.gsub(rankStr, "Rank ", ""))) or 0
-        end
+      local rankSub = C_Spell.GetSpellSubtext(spellId)
+      if rankSub and rankSub ~= "" then
+        rank = tonumber((string.gsub(rankSub, "Rank ", ""))) or 0
       end
       local playerName = UnitName("player")
       libpredict:Hot(playerName, targetName, hotType, duration, nil, "SPELL_GO_SELF", rank)

modules/castbar.lua

@@ -93,8 +93,8 @@ pfUI:RegisterModule("castbar", function ()
     cb.bar:SetStatusBarColor(strsplit(",", C.appearance.castbar[isChannel and "channelcolor" or "castbarcolor"]))
 
     local rank = ""
-    if spellID and GetSpellRecField then
-      rank = GetSpellRecField(spellID, "rank") or ""
+    if spellID then
+      rank = C_Spell.GetSpellSubtext(spellID) or ""
     end
     local spellname = (cb.showname and name) and (name .. " ") or ""
     local rankstr = (cb.showrank and rank ~= "") and string.format("|cffaaffcc[%s]|r", rank) or ""