Harden the ClassicAPI-missing path so the disable notice can show

pfUI's TOC depends on the !!!ClassicAPI addon, so a nil CLASSIC_API_VERSION
means the addon loaded but the DLL isn't present -- yet the graceful-disable
branch itself called ClassicAPI APIs (EventUtil.ContinueOnPlayerLogin, and
Mixin/CallbackRegistryMixin for pfUI.events), so it crashed instead of
informing the user.

- Defer the popup with a bare PLAYER_ENTERING_WORLD frame (stock 1.12)
  instead of EventUtil/IsLoggedIn/PLAYER_LOGIN (ClassicAPI-era).
- Read the editbox via getglobal rather than _G.
- Guard pfUI.events creation behind `not pfUI.disabled`.
- Reword the notice: since the addon is present but the DLL isn't (or is
  outdated), tell the user the addon ships bundled with the DLL and to
  delete the !!!ClassicAPI folder and (re)install the latest release.

pfUI.lua

@@ -36,9 +36,16 @@ do
   if not CLASSIC_API_VERSION or CLASSIC_API_VERSION < PFUI_CLASSIC_API_MIN then
     local minVersion = FormatVersion(PFUI_CLASSIC_API_MIN)
     pfUI.disabled = true
-    EventUtil.ContinueOnPlayerLogin(function()
+    local detail
+    if not CLASSIC_API_VERSION then
+      detail = "The ClassicAPI DLL isn't loaded. The |cff33ffcc!!!ClassicAPI|r addon ships bundled with it -- delete your |cff33ffcc!!!ClassicAPI|r folder and install the latest release from:"
+    else
+      detail = "ClassicAPI " .. minVersion .. " or newer is required. Delete your |cff33ffcc!!!ClassicAPI|r folder and reinstall the latest release from:"
+    end
+
+    local function ShowRequiredPopup()
       StaticPopupDialogs["PFUI_CLASSICAPI_REQUIRED"] = {
-        text = "This fork of |cff33ffccpf|cffffffffUI|r requires ClassicAPI\n " .. minVersion .. " or newer.\n\nAll |cff33ffccpf|cffffffffUI|r modules have been disabled.\nInstall ClassicAPI from:",
+        text = "|cff33ffccpf|cffffffffUI|r has been disabled.\n\n" .. detail,
         button1 = OKAY,
         hasEditBox = 1,
         editBoxWidth = 280,
@@ -47,7 +54,7 @@ do
         hideOnEscape = 1,
         preferredIndex = 3,
         OnShow = function()
-          local editBox = _G[this:GetName().."EditBox"]
+          local editBox = getglobal(this:GetName().."EditBox")
           if editBox then
             editBox:SetText(PFUI_CLASSIC_API_LATEST_URL)
             editBox:HighlightText()
@@ -57,9 +64,15 @@ do
       }
       StaticPopup_Show("PFUI_CLASSICAPI_REQUIRED")
       DEFAULT_CHAT_FRAME:AddMessage(
-        "This fork of |cff33ffccpf|cffffffffUI|r requires ClassicAPI " .. minVersion .. "+. Get it at " .. PFUI_CLASSIC_API_LATEST_URL,
+        "|cff33ffccpf|cffffffffUI|r disabled: " .. detail .. " " .. PFUI_CLASSIC_API_LATEST_URL,
         1, 0.3, 0.3
       )
+    end
+    local loginFrame = CreateFrame("Frame")
+    loginFrame:RegisterEvent("PLAYER_ENTERING_WORLD")
+    loginFrame:SetScript("OnEvent", function()
+      loginFrame:UnregisterEvent("PLAYER_ENTERING_WORLD")
+      ShowRequiredPopup()
     end)
   elseif CLASSIC_API_VERSION < PFUI_CLASSIC_API_LATEST then
     EventUtil.ContinueOnPlayerLogin(function()
@@ -97,9 +110,11 @@ pfUI.movables = {}
 pfUI.version = {}
 pfUI.env = {}
 
-pfUI.events = Mixin({}, CallbackRegistryMixin)
-pfUI.events:OnLoad()
-pfUI.events:SetUndefinedEventsAllowed(true)
+if not pfUI.disabled then
+  pfUI.events = Mixin({}, CallbackRegistryMixin)
+  pfUI.events:OnLoad()
+  pfUI.events:SetUndefinedEventsAllowed(true)
+end
 
 -- check if macro addons are loaded (disables macrotweak/macroscan)
 function pfUI:MacroAddonsLoaded()