fix: keep C-; ! as system command prefix

The module was binding `cj/system-command-map` under `C-; !`, then a few lines later overwriting the same prefix with `cj/system-command-menu`. The second bind won, so every documented subkey, like `C-; ! r` for reboot and `C-; ! l` for lock, was unreachable.

I kept the prefix map and folded the completing-read menu into it at `C-; ! !`. So `C-; !` still opens the prefix, the menu is one extra `!` away, and the single-letter shortcuts work again. I also added which-key labels for every documented subkey so the popup actually says what each one does.

I added `tests/test-system-commands-keymap.el`. It asserts the prefix stays mounted and that every binding (`!`, `L`, `r`, `s`, `S`, `l`, `E`, `e`) resolves to the right command.

2 files changed, 57 insertions, 13 deletions

diff --git a/modules/system-commands.el b/modules/system-commands.el
index fb8c0611..8b155746 100644
--- a/modules/system-commands.el
+++ b/modules/system-commands.el
@@ -104,17 +104,6 @@ If CONFIRM is non-nil, mark VAR to always require confirmation."
   (run-at-time 1 nil #'kill-emacs)
   (message "Restarting Emacs..."))
 
-(defvar-keymap cj/system-command-map
-  :doc "Keymap for system commands."
-  "L" #'cj/system-cmd-logout
-  "r" #'cj/system-cmd-reboot
-  "s" #'cj/system-cmd-shutdown
-  "S" #'cj/system-cmd-suspend
-  "l" #'cj/system-cmd-lock
-  "E" #'cj/system-cmd-exit-emacs
-  "e" #'cj/system-cmd-restart-emacs)
-(keymap-set cj/custom-keymap "!" cj/system-command-map)
-
 (defun cj/system-command-menu ()
   "Present system commands via \='completing-read\='."
   (interactive)
@@ -129,10 +118,29 @@ If CONFIRM is non-nil, mark VAR to always require confirmation."
     (when-let ((cmd (alist-get choice commands nil nil #'equal)))
       (call-interactively cmd))))
 
-(keymap-set cj/custom-keymap "!" #'cj/system-command-menu)
+(defvar-keymap cj/system-command-map
+  :doc "Keymap for system commands."
+  "!" #'cj/system-command-menu
+  "L" #'cj/system-cmd-logout
+  "r" #'cj/system-cmd-reboot
+  "s" #'cj/system-cmd-shutdown
+  "S" #'cj/system-cmd-suspend
+  "l" #'cj/system-cmd-lock
+  "E" #'cj/system-cmd-exit-emacs
+  "e" #'cj/system-cmd-restart-emacs)
+(keymap-set cj/custom-keymap "!" cj/system-command-map)
 
 (with-eval-after-load 'which-key
-  (which-key-add-key-based-replacements "C-; !" "system commands"))
+  (which-key-add-key-based-replacements
+    "C-; !" "system commands"
+    "C-; ! !" "system command menu"
+    "C-; ! L" "logout"
+    "C-; ! E" "exit Emacs"
+    "C-; ! S" "suspend"
+    "C-; ! e" "restart Emacs"
+    "C-; ! l" "lock screen"
+    "C-; ! r" "reboot"
+    "C-; ! s" "shutdown"))
 
 (provide 'system-commands)
 ;;; system-commands.el ends here
diff --git a/tests/test-system-commands-keymap.el b/tests/test-system-commands-keymap.el
new file mode 100644
index 00000000..ac78a25d
--- /dev/null
+++ b/tests/test-system-commands-keymap.el
@@ -0,0 +1,36 @@
+;;; test-system-commands-keymap.el --- Tests for system command keymap -*- lexical-binding: t; -*-
+
+;;; Commentary:
+
+;; The system command keymap should remain mounted as a prefix under C-; ! so
+;; which-key can show the documented subcommands.
+
+;;; Code:
+
+(require 'ert)
+
+(defvar cj/custom-keymap (make-sparse-keymap)
+  "Stub custom keymap for system-commands tests.")
+
+(require 'system-commands)
+
+(ert-deftest test-system-commands-keymap-normal-prefix-mounted ()
+  "Normal: C-; ! remains a prefix keymap, not a direct command."
+  (should (eq (keymap-lookup cj/custom-keymap "!")
+              cj/system-command-map)))
+
+(ert-deftest test-system-commands-keymap-normal-documented-subkeys ()
+  "Normal: documented system command subkeys resolve under the prefix."
+  (dolist (binding '(("!" . cj/system-command-menu)
+                     ("L" . cj/system-cmd-logout)
+                     ("r" . cj/system-cmd-reboot)
+                     ("s" . cj/system-cmd-shutdown)
+                     ("S" . cj/system-cmd-suspend)
+                     ("l" . cj/system-cmd-lock)
+                     ("E" . cj/system-cmd-exit-emacs)
+                     ("e" . cj/system-cmd-restart-emacs)))
+    (should (eq (keymap-lookup cj/system-command-map (car binding))
+                (cdr binding)))))
+
+(provide 'test-system-commands-keymap)
+;;; test-system-commands-keymap.el ends here