chore(frontend): adds favicon

frontend/index.html

@@ -4,6 +4,7 @@
     <meta charset="UTF-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <meta name="theme-color" content="#0f172a" />
+    <link rel="icon" href="/favicon.svg" type="image/svg+xml" />
     <title>Семейный бюджет</title>
     <link rel="preconnect" href="https://fonts.googleapis.com" />
     <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin />

frontend/public/favicon.svg

@@ -0,0 +1,4 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 32 32" fill="none">
+  <rect width="32" height="32" rx="8" fill="#0f172a"/>
+  <text x="16" y="23" font-family="Georgia, serif" font-size="20" font-weight="bold" fill="#3b82f6" text-anchor="middle">&#8381;</text>
+</svg>