Fix PWA manifest error in dev, handle invalid font data

Remove hardcoded manifest link from index.html (VitePWA injects
it in production builds). Catch FontFace.load() rejections from
invalid font data with a warning.

index.html

@@ -8,7 +8,6 @@
     <link rel="apple-touch-icon" href="/apple-touch-icon.png" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no, viewport-fit=cover" />
     <meta name="theme-color" content="#1e1e1e" />
-    <link rel="manifest" href="/manifest.webmanifest" />
     <title>OpenPencil</title>
     <style>
       body { margin: 0; background: #1e1e1e; }

packages/core/src/fonts.ts

@@ -191,7 +191,9 @@ function registerFontInBrowser(family: string, style: string, data: ArrayBuffer)
     weight: String(weight),
     style: italic
   })
-  face.load().then(() => document.fonts.add(face))
+  face.load().then(() => document.fonts.add(face)).catch(() => {
+    console.warn(`Failed to load font "${family}" (${style})`)
+  })
 }
 
 export function styleToWeight(style: string): number {