fix web review validation and clipboard tests

apps/web/src/features/auth/ServerLogin.svelte

@@ -13,7 +13,7 @@
       return { error: 'Enter a server address.' };
     }
 
-    if (hasWhitespace(value) || hasUnsupportedProtocol(value)) {
+    if (hasWhitespace(value) || value.includes('\\') || hasMalformedHttpProtocol(value) || hasUnsupportedProtocol(value)) {
       return { error: 'Enter a valid HTTP or HTTPS server address.' };
     }
 
@@ -58,6 +58,10 @@
     return /^[a-z][a-z\d+.-]*:(?!\d)/i.test(value);
   }
 
+  function hasMalformedHttpProtocol(value: string): boolean {
+    return /^https?:\/(?!\/)/i.test(value) || /^https?\/{2}(?!\/)/i.test(value);
+  }
+
   function hasCredentials(value: string): boolean {
     const authority = value.replace(/^https?:\/\//i, '').split(/[/?#]/, 1)[0];
     return authority.includes('@');