replace poll-until-cancel OnUpdate frames with C_Timer / RunNextFrame

Seven ad-hoc OnUpdate handlers were only spinning long enough to reach
a known deadline or a next-frame defer, then unhooking themselves.
Convert them to their proper primitives:

- autovendor: 0.3s wait after junk sell → C_Timer.After(0.3, ...)
- innervatecall: cooldown-expiry ready ping → C_Timer.After(cd, ...)
- focus: re-arm UI_ERROR_MESSAGE next tick → RunNextFrame
- macrotweak: conflict scan after addons load → RunNextFrame
- ui-widgets (CreateQuestionDialog): font-measure resize → RunNextFrame
- libdebuff: post-PEW Nampower init → RunNextFrame
- bubbles: WorldFrame scan after chat event → RunNextFrame

Net -18 lines and no more throwaway frames sitting on the OnUpdate list.

modules/focus.lua

@@ -50,10 +50,8 @@ function SlashCmdList.PFFOCUSNAME(msg)
     FocusUnit("target")
   end
 
-  local restore = CreateFrame("Frame")
-  restore:SetScript("OnUpdate", function()
+  RunNextFrame(function()
     UIErrorsFrame:RegisterEvent("UI_ERROR_MESSAGE")
-    restore:SetScript("OnUpdate", nil)
   end)
 
   if prevGUID and prevGUID ~= "0x0000000000000000" then