feat(frontend): installable on the phone with its own icon, title and manifest, missing avatars are asked again later

frontend/src/app.html

@@ -1,9 +1,18 @@
 <!doctype html>
-<html lang="en">
+<html lang="ru">
 	<head>
 		<meta charset="utf-8" />
 		<meta content="width=device-width, initial-scale=1" name="viewport" />
 		<meta content="scale" name="text-scale" />
+		<meta content="#ffffff" media="(prefers-color-scheme: light)" name="theme-color" />
+		<meta content="#212121" media="(prefers-color-scheme: dark)" name="theme-color" />
+		<meta content="yes" name="mobile-web-app-capable" />
+		<meta content="black-translucent" name="apple-mobile-web-app-status-bar-style" />
+		<meta content="Beavergram" name="apple-mobile-web-app-title" />
+		<link href="/icon.svg" rel="icon" type="image/svg+xml" />
+		<link href="/apple-touch-icon.png" rel="apple-touch-icon" />
+		<link href="/manifest.webmanifest" rel="manifest" />
+		<title>Beavergram</title>
 		<script>
 			(() => {
 				const stored = localStorage.getItem("bg.theme");