feat(settings): implement persistent auto-refresh functionality

Adds a configurable and persistable auto-refresh setting to the application's settings dialog. This feature allows users to control whether the repository view automatically updates its status, branch information, and remote tracking in the background. The logic is integrated across core components to manage state changes and provide visual feedback to the user.

- Auto-refresh state is now persistent and managed via local storage.
- Updated settings dialog UI to include a dedicated toggle for auto-refresh.
- Removed manual auto-refresh toggling from the repository toolbar component.

src/lib/RepoToolbar.svelte

@@ -18,8 +18,6 @@
   export let operation: string = "";
   export let ahead: number = 0;
   export let behind: number = 0;
-  export let autoRefreshEnabled: boolean = true;
-  export let autoRefreshInFlight: boolean = false;
   export let language: "en" | "de" = "en";
   export let onFetch: () => void = () => {};
   export let onPull: () => void = () => {};
@@ -30,7 +28,6 @@
   export let onInteractiveRebase: () => void = () => {};
   export let onReflog: () => void = () => {};
   export let onOpenInExplorer: () => void = () => {};
-  export let onToggleAutoRefresh: () => void = () => {};
 
   let historyOpen = false;
   let toolbarElement: HTMLDivElement;
@@ -192,26 +189,14 @@
     </button>
 
     <button
-      class="repo-action icon-action"
+      class="repo-action"
       onclick={onRefresh}
       disabled={isBusy || !hasRepository}
       title={isGerman ? "Manuell aktualisieren" : "Refresh now"}
       aria-label={isGerman ? "Manuell aktualisieren" : "Refresh now"}
     >
-      <RefreshCw class={operation === "Refreshing" ? "spin" : ""} size={15} aria-hidden="true" />
-    </button>
-
-    <button
-      class="repo-auto-toggle"
-      class:active={autoRefreshEnabled}
-      onclick={onToggleAutoRefresh}
-      aria-pressed={autoRefreshEnabled}
-      title={autoRefreshEnabled
-        ? (isGerman ? "Auto-Aktualisierung ausschalten" : "Turn auto-refresh off")
-        : (isGerman ? "Auto-Aktualisierung einschalten" : "Turn auto-refresh on")}
-    >
-      <span>{isGerman ? "Auto" : "Auto"}</span>
-      <span class="repo-switch" class:busy={autoRefreshInFlight} aria-hidden="true"><span></span></span>
+      <RefreshCw class={operation === "Refreshing" ? "spin" : ""} size={16} aria-hidden="true" />
+      <span class="repo-action-label utility-label">{isGerman ? "Aktualisieren" : "Refresh"}</span>
     </button>
   </div>
 </div>