Adds self-hosted update system

Implements a self-hosted update mechanism, allowing the application to be updated from a corporate network share without relying on third-party services.

This includes:
- Functionality to check for updates
- Download installers
- Verify checksums
- Install updates with UAC elevation

Configuration is managed via the config.ini file, with automatic checks on startup. A new settings UI is also included.

frontend/src/routes/(app)/+layout.svelte

@@ -39,6 +39,8 @@
     WindowUnmaximise,
     WindowIsMaximised,
     Quit,
+    EventsOn,
+    EventsOff,
   } from "$lib/wailsjs/runtime/runtime";
   import { RefreshCcwDot } from "@lucide/svelte";
   import { IsDebuggerRunning, QuitApp, TakeScreenshot, SubmitBugReport, OpenFolderInExplorer } from "$lib/wailsjs/go/main/App";
@@ -162,6 +164,26 @@
     }
   });
 
+  // Listen for automatic update notifications
+  $effect(() => {
+    if (!browser) return;
+
+    EventsOn("update:available", (status: any) => {
+      toast.info(`Update ${status.availableVersion} is available!`, {
+        description: "Go to Settings to download and install",
+        duration: 10000,
+        action: {
+          label: "Open Settings",
+          onClick: () => goto("/settings"),
+        },
+      });
+    });
+
+    return () => {
+      EventsOff("update:available");
+    };
+  });
+
   async function captureScreenshot() {
     isCapturing = true;
     try {