Fix demo user confirmation to allow password login

The seeds file was creating an unconfirmed user and then setting a password,
which conflicts with Phoenix's auth system (magic link login is not allowed
for unconfirmed users with passwords).

This fix ensures the demo user is confirmed before setting their password,
so they can log in via both magic link and password.

Demo credentials: demo@example.com / password123!

app/priv/repo/seeds.exs

@@ -11,11 +11,29 @@
 # and so on) as they will fail if something goes wrong.
 
 if Mix.env() == :dev do
+  import Ecto.Query
   alias Firehose.Accounts
 
-  # Create demo user if not already present
-  unless Accounts.get_user_by_email("demo@example.com") do
+  # Get or create demo user
+  user = Accounts.get_user_by_email("demo@example.com")
+
+  unless user do
     {:ok, user} = Accounts.register_user(%{email: "demo@example.com"})
+  end
+
+  # Ensure user is confirmed to allow password login and avoid magic link conflicts
+  if is_nil(user.confirmed_at) do
+    Firehose.Repo.update_all(
+      from(u in Accounts.User, where: u.email == ^"demo@example.com"),
+      set: [confirmed_at: DateTime.utc_now()]
+    )
+
+    # Reload user after confirmation
+    user = Accounts.get_user_by_email("demo@example.com")
+  end
+
+  # Set password if not already set
+  unless user.hashed_password do
     {:ok, {_user, _tokens}} = Accounts.update_user_password(user, %{password: "password123!"})
   end
 end