feat: implement console logger with backend integration and file logging

frontend/src/lib/utils/logger-hook.ts

@@ -0,0 +1,56 @@
+import { FrontendLog } from '$lib/wailsjs/go/main/App';
+
+function safeStringify(obj: any): string {
+    try {
+        if (typeof obj === 'object' && obj !== null) {
+             return JSON.stringify(obj);
+        }
+        return String(obj);
+    } catch (e) {
+        return '[Circular/Error]';
+    }
+}
+
+export function setupConsoleLogger() {
+    if ((window as any).__logger_initialized__) return;
+    (window as any).__logger_initialized__ = true;
+
+    const originalLog = console.log;
+    const originalWarn = console.warn;
+    const originalError = console.error;
+    const originalInfo = console.info;
+
+    function logToBackend(level: string, args: any[]) {
+        try {
+            // Avoid logging if wails runtime is not ready or function is missing
+            if (typeof FrontendLog !== 'function') return;
+
+            const message = args.map(arg => safeStringify(arg)).join(' ');
+            FrontendLog(level, message).catch(() => {});
+        } catch (e) {
+            // ignore
+        }
+    }
+
+    console.log = (...args) => {
+        originalLog(...args);
+        logToBackend("INFO", args);
+    };
+
+    console.warn = (...args) => {
+        originalWarn(...args);
+        logToBackend("WARN", args);
+    };
+
+    console.error = (...args) => {
+        originalError(...args);
+        logToBackend("ERROR", args);
+    };
+
+    console.info = (...args) => {
+        originalInfo(...args);
+        logToBackend("INFO", args);
+    };
+
+    originalLog("Console logger hooked to Wails backend");
+}

frontend/src/lib/wailsjs/go/main/App.d.ts

@@ -6,6 +6,8 @@ import {internal} from '../models';
 
 export function CheckIsDefaultEMLHandler():Promise<boolean>;
 
+export function FrontendLog(arg1:string,arg2:string):Promise<void>;
+
 export function GetConfig():Promise<utils.Config>;
 
 export function GetImageViewerData():Promise<main.ImageViewerData>;

frontend/src/lib/wailsjs/go/main/App.js

@@ -6,6 +6,10 @@ export function CheckIsDefaultEMLHandler() {
   return window['go']['main']['App']['CheckIsDefaultEMLHandler']();
 }
 
+export function FrontendLog(arg1, arg2) {
+  return window['go']['main']['App']['FrontendLog'](arg1, arg2);
+}
+
 export function GetConfig() {
   return window['go']['main']['App']['GetConfig']();
 }

frontend/src/routes/+layout.svelte

@@ -1,9 +1,11 @@
 <script lang="ts">
 	import { onMount } from 'svelte';
+	import { setupConsoleLogger } from '$lib/utils/logger-hook';
 
 	let { children } = $props();
 
 	onMount(() => {
+		setupConsoleLogger();
 		const loader = document.getElementById('app-loading');
 		if (loader) {
 			loader.style.opacity = '0';