feat: add Cmd-B sidebar toggle shortcut (#1775)

Co-authored-by: Dr. Lukas Metzger <lukas@mba.lan>
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

src/ui/shell/keybinding-registry.ts

@@ -84,6 +84,11 @@ const SHELL_ACTIONS: KeybindingActionDef[] = [
     "newUi.sidebar.keybindings.actionReconnectSession",
     1003,
   ),
+  shellAction(
+    "toggleSidebar",
+    "newUi.sidebar.keybindings.actionToggleSidebar",
+    1004,
+  ),
 ];
 
 export const SHELL_KEYBINDING_ACTION_IDS = SHELL_ACTIONS.map(
@@ -97,6 +102,21 @@ function install(): void {
   for (const action of SHELL_ACTIONS) {
     if (!actions.get(action.id)) actions.register(action);
   }
+  if (!defaults.get("toggleSidebar")) {
+    defaults.register({
+      id: "toggleSidebar",
+      combo: {
+        key: "KeyB",
+        isCode: true,
+        ctrl: false,
+        alt: false,
+        shift: false,
+        meta: true,
+      },
+      descriptionKey: "newUi.sidebar.keybindings.actionToggleSidebar",
+      order: 1004,
+    });
+  }
 }
 install();