test: fix test auth and improve reliability

- Add admin authentication to all tests
- Fix 12 tests that were failing due to missing authentication
- 3 tests still have business logic issues (will fix separately)

test/support/fixtures.ex

@@ -0,0 +1,96 @@
+defmodule Mv.Fixtures do
+  @moduledoc """
+  Shared test fixtures for consistent test data creation.
+
+  This module provides factory functions for creating test data across
+  different test suites, ensuring consistency and reducing duplication.
+  """
+
+  @doc """
+  Creates a member with default or custom attributes.
+
+  ## Parameters
+    - `attrs` - Map or keyword list of attributes to override defaults
+
+  ## Returns
+    - Member struct
+
+  ## Examples
+
+      iex> member_fixture()
+      %Mv.Membership.Member{first_name: "Test", ...}
+
+      iex> member_fixture(%{first_name: "Alice", email: "alice@example.com"})
+      %Mv.Membership.Member{first_name: "Alice", email: "alice@example.com"}
+
+  """
+  def member_fixture(attrs \\ %{}) do
+    attrs
+    |> Enum.into(%{
+      first_name: "Test",
+      last_name: "Member",
+      email: "test#{System.unique_integer([:positive])}@example.com"
+    })
+    |> Mv.Membership.create_member()
+    |> case do
+      {:ok, member} -> member
+      {:error, error} -> raise "Failed to create member: #{inspect(error)}"
+    end
+  end
+
+  @doc """
+  Creates a user with default or custom attributes.
+
+  ## Parameters
+    - `attrs` - Map or keyword list of attributes to override defaults
+
+  ## Returns
+    - User struct
+
+  ## Examples
+
+      iex> user_fixture()
+      %Mv.Accounts.User{email: "user123@example.com"}
+
+      iex> user_fixture(%{email: "custom@example.com"})
+      %Mv.Accounts.User{email: "custom@example.com"}
+
+  """
+  def user_fixture(attrs \\ %{}) do
+    attrs
+    |> Enum.into(%{
+      email: "user#{System.unique_integer([:positive])}@example.com"
+    })
+    |> Mv.Accounts.create_user()
+    |> case do
+      {:ok, user} -> user
+      {:error, error} -> raise "Failed to create user: #{inspect(error)}"
+    end
+  end
+
+  @doc """
+  Creates a user linked to a member.
+
+  ## Parameters
+    - `user_attrs` - Map or keyword list of user attributes
+    - `member_attrs` - Map or keyword list of member attributes
+
+  ## Returns
+    - Tuple of {user, member}
+
+  ## Examples
+
+      iex> {user, member} = linked_user_member_fixture()
+      iex> user.member_id == member.id
+      true
+
+  """
+  def linked_user_member_fixture(user_attrs \\ %{}, member_attrs \\ %{}) do
+    member = member_fixture(member_attrs)
+
+    user_attrs = Map.put(user_attrs, :member, %{id: member.id})
+    user = user_fixture(user_attrs)
+
+    {user, member}
+  end
+end