Debounce jump-to-end against append-induced focus perturbation

The tostring() comparison fix wasn't sufficient - jump-to-end was still
firing on nearly every incoming line while jump-to-end-on-focus was on.
AppendToNotepad's own SetSel/ReplaceSel appears to momentarily perturb
GetFocus() around each append, which poll_output_focus was reading as a
genuine "just switched to the window" edge. Now skips the jump if a
SmartAppendToNotepad call happened within the last 0.5s.

cosmic rage/worlds/plugins/output_functions.xml

@@ -407,7 +407,11 @@ end
 -- Note: text should use "\r\n" line endings, not bare "\n" - the plain
 -- Win32 Edit control that backs the notepad doesn't recognise bare "\n"
 -- as a line break for scrolling/line-count purposes.
+last_append_clock = 0
+
 function SmartAppendToNotepad(title, text)
+  last_append_clock = os.clock()
+
   local edit = find_notepad_edit(title)
   local was_at_end = true
   local sel_start, sel_end, first_visible
@@ -474,7 +478,14 @@ function poll_output_focus()
  -- fell back to identity comparison), causing spurious "just gained
  -- focus" edges and repeated jump-to-end even while focus never moved.
  local is_focused = (tostring(focused) == tostring(edit))
- if is_focused and not was_output_focused then
+ -- Skip the jump if a SmartAppendToNotepad call happened very recently:
+ -- AppendToNotepad's own SetSel/ReplaceSel appears to momentarily
+ -- perturb GetFocus() around each append, which was making this poll
+ -- see a spurious "just gained focus" edge - and jump to the end - on
+ -- practically every incoming line, even though the user never left
+ -- the window.
+ local recent_append = (os.clock() - last_append_clock) < 0.5
+ if is_focused and not was_output_focused and not recent_append then
   jump_notepad_to_end(edit)
  end
  was_output_focused = is_focused