fix(key-bindings): make numeric keypad work in application mode

We switch the terminal into application keypad mode (smkx) so terminfo
key bindings are valid, but that also makes the numeric keypad send
escape sequences (\eOp..\eOy, \eOM, ...) that were never bound. Keypad
Enter rang the bell instead of running the command.

Map each keypad sequence back to the plain key with `bindkey -s`, so it
behaves exactly like the main keyboard key in emacs, viins and vicmd.

Fixes #13928

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

lib/key-bindings.zsh

@@ -110,6 +110,23 @@ bindkey -M emacs '^[[1;5D' backward-word
 bindkey -M viins '^[[1;5D' backward-word
 bindkey -M vicmd '^[[1;5D' backward-word
 
+# [Keypad] - application mode (enabled above) makes the keypad send escape
+# sequences instead of characters, so map them back to the plain keys
+() {
+  local seq key
+  local -A keypad=(
+    '^[Op' '0' '^[Oq' '1' '^[Or' '2' '^[Os' '3' '^[Ot' '4'
+    '^[Ou' '5' '^[Ov' '6' '^[Ow' '7' '^[Ox' '8' '^[Oy' '9'
+    '^[On' '.' '^[Ol' ',' '^[Ok' '+' '^[Om' '-' '^[Oj' '*'
+    '^[Oo' '/' '^[OX' '=' '^[OM' '^M'
+  )
+  for seq key in "${(@kv)keypad}"; do
+    bindkey -M emacs -s "$seq" "$key"
+    bindkey -M viins -s "$seq" "$key"
+    bindkey -M vicmd -s "$seq" "$key"
+  done
+}
+
 
 bindkey '\ew' kill-region                             # [Esc-w] - Kill from the cursor to the mark
 bindkey -s '\el' '^q ls\n'                            # [Esc-l] - run command: ls