fix: allow custom callback for email link sign-in

Author: russellwheatley

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Services/AuthService.swift

@@ -141,6 +141,7 @@ public final class AuthService {
   private var listenerManager: AuthListenerManager?
 
   var emailSignInEnabled = false
+  private var emailSignInCallback: (@MainActor () -> Void)?
 
   private var providers: [AuthProviderUI] = []
 
@@ -151,12 +152,18 @@ public final class AuthService {
   public func renderButtons(spacing: CGFloat = 16) -> AnyView {
     AnyView(
       VStack(spacing: spacing) {
-        AuthProviderButton(
-          label: string.signInWithEmailLinkViewTitle,
-          style: .email,
-          accessibilityId: "sign-in-with-email-link-button"
-        ) {
-          self.navigator.push(.emailLink)
+        if emailSignInEnabled {
+          AuthProviderButton(
+            label: string.signInWithEmailLinkViewTitle,
+            style: .email,
+            accessibilityId: "sign-in-with-email-link-button"
+          ) {
+            if let callback = self.emailSignInCallback {
+              callback()
+            } else {
+              self.navigator.push(.emailLink)
+            }
+          }
         }
         ForEach(providers, id: \.id) { provider in
           provider.authButton()
@@ -309,8 +316,17 @@ public extension AuthService {
 // MARK: - Email/Password Sign In
 
 public extension AuthService {
+  /// Enable email sign-in with default behavior (navigates to email link view)
   func withEmailSignIn() -> AuthService {
+    return withEmailSignIn { [weak self] in
+      self?.navigator.push(.emailLink)
+    }
+  }
+
+  /// Enable email sign-in with custom callback
+  func withEmailSignIn(onTap: @escaping @MainActor () -> Void) -> AuthService {
     emailSignInEnabled = true
+    emailSignInCallback = onTap
     return self
   }