Add Hacker News guidelines button to login screen (#354)

Added button to open Hacker New's Guidelines 
![Simulator Screenshot - iPhone 16 Pro - 2025-02-04 at 17 52
18](https://github.com/user-attachments/assets/cf5cfea7-048d-421a-a765-2797dc180f9e)

ios/HackerNews/Auth/LoginScreen.swift

@@ -64,6 +64,20 @@ struct LoginScreen: View {
           .font(.ibmPlexMono(.regular, size: 14))
       }
 
+
+      HStack(spacing: 0) {
+        Text("By signing in, you agree to the ")
+          .font(.ibmPlexSans(.regular, size: 12))
+        Text("Hacker News Guidelines")
+          .font(.ibmPlexSans(.regular, size: 12))
+          .foregroundColor(.blue)
+          .underline()
+          .onTapGesture {
+            openURL("https://news.ycombinator.com/newsguidelines.html")
+          }
+        Spacer()
+      }
+
       Spacer()
         .frame(maxHeight: 16)
 
@@ -96,6 +110,11 @@ struct LoginScreen: View {
     .padding(32)
     .background(.surface)
   }
+
+  func openURL(_ urlString: String) {
+    guard let url = URL(string: urlString) else { return }
+    UIApplication.shared.open(url, options: [:], completionHandler: nil)
+  }
 }
 
 #Preview("Default") {