fix(org): show org logo for favicon and OG image (#713)

When no custom favicon is set, fall back to the organization logo on
public org-site pages instead of the default ClassroomIO icon.

For OG images, only apply the theme-color background behind the logo
when rendering initials; real logo images now render without the tint.

Co-authored-by: Cursor Agent <cursoragent@cursor.com>
Co-authored-by: Rotimi Best <rotimi-best@users.noreply.github.com>

apps/dashboard/src/app.html

@@ -6,8 +6,6 @@
     <meta name="theme-color" content="#333333" />
 
     <link rel="manifest" href="/manifest.json" crossorigin="use-credentials" />
-    <link rel="icon" type="image/png" href="/favicon.ico" />
-    <link rel="icon" type="image/png" sizes="32x32" href="/logo-32.png" />
 
     %sveltekit.head%
   </head>