fix(ui2): ENTER may focus pager in insert/terminal mode #38497

fix(ui2): prevent <CR> from focusing pager in insert/terminal mode

Problem:  <CR> in insert/terminal mode can focus pager unexpectedly.
Solution: Don't enter the pager when <CR> is pressed during expanded
          cmdline in insert/terminal mode.

runtime/lua/vim/_core/ui2.lua

@@ -43,7 +43,7 @@
 --- Unlike the legacy |hit-enter| prompt, messages exceeding 'cmdheight' are
 --- instead "collapsed", followed by a `[+x]` "spill" indicator, where `x`
 --- indicates the spilled lines. To see the full messages, do either:
---- - ENTER immediately after a message from interactive |:| cmdline.
+--- - ENTER while cmdline is expanded (not in |Insert-mode| and |Terminal-mode|).
 --- - |g<| at any time.
 
 local api = vim.api

runtime/lua/vim/_core/ui2/messages.lua

@@ -517,7 +517,7 @@ local cmd_on_key = function(_, typed)
   M.cmd_on_key, M.cmd.ids = nil, {}
 
   -- Check if window was entered and reopen with original config.
-  local entered = typed == '<CR>'
+  local entered = typed == '<CR>' and not api.nvim_get_mode().mode:match('[it]')
     or typed:find('LeftMouse') and fn.getmousepos().winid == ui.wins.cmd
   pcall(api.nvim_win_close, ui.wins.cmd, true)
   ui.check_targets()