phase 2 removing tbc

Strip dead pfUI.client > 11200 and pfUI.expansion == "tbc" branches now
that vanilla is the only supported client.

- pfUI.lua: hardcode expansion = "vanilla"; collapse force_region matrix
- compat/vanilla.lua, libs/{libcast,libdebuff,libtotem,libunitscan,
  focus}: drop always-false early-returns
- api/unitframes.lua: delete TargetBuffOnUpdate poller + tbc visibility
  and secure-template branches; click-cast keeps only vanilla path
- api/ui-widgets.lua: unconditional EffectiveScale divide
- env/tables.lua: drop unused focus/focustarget pfValidUnits entries
- modules/actionbar.lua: simplify EnablePaging, drop ButtonSwitch/
  petvisibility, unwrap prowl block, single keybind-remap path
- modules/{castbar,chat,cooldown,loot,questitem,totems}: unwrap
  always-true conditionals
- modules/nameplates.lua: cfg-only fake-cooldown gate, unwrap overlap/
  clickthrough + mouselook blocks
- modules/friends.lua + skins/blizzard/friends.lua: maxtab = 4
- skins/blizzard/{help,game_menu,questlog}: drop tbc-only branches

modules/totems.lua

@@ -15,7 +15,7 @@ pfUI:RegisterModule("totems", "vanilla:tbc", function ()
     totems:RefreshList()
   end)
 
-  if pfUI.client <= 11200 and class == "SHAMAN" then
+  if class == "SHAMAN" then
     -- there's no totem event in vanilla using ticks instead
     local eventemu = CreateFrame("Frame")
     eventemu:SetScript("OnUpdate", function()
@@ -39,13 +39,10 @@ end
   end
 
   totems.OnClick = function(self)
-    if pfUI.client <= 11200 and this.id and arg1 and arg1 == "LeftButton" then
-      -- Try to recast totem on left click in vanilla
+    if this.id and arg1 and arg1 == "LeftButton" then
+      -- Try to recast totem on left click
       local active, name, start, duration, icon = GetTotemInfo(this.id)
       if name then CastSpellByName(name) end
-    elseif pfUI.client > 11200 and this.id and arg1 and arg1 == "RightButton" then
-      -- Try to cancel totem on right click in tbc+
-      DestroyTotem(this.id)
     end
   end