feat(sessions): implement local user session switching functionality

- Core user is logged in tty1 while user two is in tty3, you can now seamlessly switch bewteen them
New IPC options:
- `dms ipc call sessions list`
- `dms switch-user [target]`
- New Powermenu switch users option

quickshell/Modals/PowerMenuModal.qml

@@ -81,6 +81,8 @@ DankModal {
         executeAction(action);
     }
 
+    signal switchUserRequested
+
     function executeAction(action) {
         if (action === "lock") {
             close();
@@ -92,6 +94,11 @@ DankModal {
             Quickshell.execDetached(["dms", "restart"]);
             return;
         }
+        if (action === "switchuser") {
+            close();
+            switchUserRequested();
+            return;
+        }
         close();
         root.powerActionRequested(action, "", "");
     }
@@ -216,6 +223,12 @@ DankModal {
                 "label": I18n.tr("Restart DMS"),
                 "key": "D"
             };
+        case "switchuser":
+            return {
+                "icon": "switch_account",
+                "label": I18n.tr("Switch User"),
+                "key": "U"
+            };
         default:
             return {
                 "icon": "help",