ement: auto-connect on startup, my/ement-open, remove ement-sync binding

- my/ement-maybe-restore: restores saved session on after-init-hook,
  no credentials prompt (requires one manual login first)
- my/ement-open: SPC o M o — connects if needed, then ement-list-rooms
- Remove SPC o M s (ement-sync is internal, manual call causes double-loop)
- Update quick reference comments

config.el

@@ -852,20 +852,21 @@ Keeps the status bar and tab bar fully visible at any zoom level.")
 ;; Matrix client. Package declared in packages.el.
 ;; Keybindings: SPC o M (open → matrix)
 ;; Note: SPC o m is taken by Doom's mu4e module (#'mu4e), hence uppercase M.
-;; E2EE: connect via Pantalaimon proxy (see notes/emacs-matrix.org)
 ;;
 ;; Quick reference:
-;;   SPC o M c  — connect (ement-connect)
+;;   SPC o M o  — open Matrix panel (connect + room list, no credentials)
+;;   SPC o M c  — connect / re-connect manually
+;;   SPC o M C  — disconnect
 ;;   SPC o M l  — list rooms
 ;;   SPC o M r  — open room
 ;;   SPC o M d  — direct message
 
 (after! ement
 
-  ;; Persist session across restarts (token stored in ~/.cache/emacs/ement.el)
+  ;; Persist session across restarts (saved token = no credentials on next start)
   (setq ement-save-sessions t)
 
-  ;; Background auto-sync
+  ;; Background auto-sync (internal — do NOT call ement-sync manually, causes issues)
   (setq ement-auto-sync t)
 
   ;; Show timestamp on every message
@@ -877,11 +878,29 @@ Keeps the status bar and tab bar fully visible at any zoom level.")
 
   ;; Notify on mentions (@martin)
   (setq ement-notify-mentions-p t
-        ement-notify-dingalings-p nil)) ; no sound
+        ement-notify-dingalings-p nil) ; no sound
+
+  ;; Auto-connect on startup: restore saved session without prompting for credentials.
+  ;; Activates only when session file exists (requires one manual ement-connect first).
+  (defun my/ement-maybe-restore ()
+    "Restore saved ement session silently (no credentials prompt)."
+    (when (file-exists-p (expand-file-name ement-sessions-file))
+      (ement-connect :user-id "@martin:sukany.cz")))
+
+  ;; Open Matrix panel: restore/connect if needed, then show room list.
+  (defun my/ement-open ()
+    "Switch to Matrix: reconnect if needed, then open room list."
+    (interactive)
+    (if (and (boundp 'ement-sessions) ement-sessions)
+        (ement-list-rooms)
+      (my/ement-maybe-restore)))
+
+  (add-hook 'after-init-hook #'my/ement-maybe-restore))
 
 ;; Keybindings under SPC o M (uppercase M — o m is taken by mu4e)
 (map! :leader
       (:prefix ("o M" . "Matrix")
+       :desc "Open panel"           "o" #'my/ement-open
        :desc "Connect"              "c" #'ement-connect
        :desc "Disconnect"           "C" #'ement-disconnect
        :desc "List rooms"           "l" #'ement-list-rooms
@@ -889,5 +908,4 @@ Keeps the status bar and tab bar fully visible at any zoom level.")
        :desc "Direct message"       "d" #'ement-send-direct-message
        :desc "Join room"            "j" #'ement-join-room
        :desc "Notifications"        "n" #'ement-notifications
-       :desc "Mentions"             "m" #'ement-mentions
-       :desc "Sync"                 "s" #'ement-sync))
+       :desc "Mentions"             "m" #'ement-mentions))