fix(ui): make logo clickable on profile, admin, and shared pages

Follow-up to ce9971b — the logo was only fixed in index.html.
Now profile.html, admin.html, and shared.html also wrap their
logo elements in <a href='/'> links.

Fixes #97

static/admin.html

@@ -201,11 +201,11 @@ details[open] summary{margin-bottom:14px;color:#ff5e3a}
 <!-- Header -->
 <div class="admin-header">
   <div class="admin-header-left">
-    <div class="admin-logo">
+    <a href="/" class="admin-logo" style="text-decoration:none">
       <svg viewBox="0 0 500 500">
         <path d="M345 310c32 0 58-26 58-58s-26-58-58-58c-6.2 0-12 0.9-17.5 2.7C318 166 289 143 255 143c-34.3 0-63.1 22.6-73 53.7C176.9 195.7 171 195 165 195c-32 0-58 26-58 58s26 58 58 58h180z"/>
       </svg>
-    </div>
+    </a>
     <div class="admin-title">OxiCloud <span>· Admin</span></div>
   </div>
   <div class="admin-header-right">