Fix changelog page crash when GitHub release notes are unavailable (#2314)

* Fix changelog page crash when GitHub release notes are unavailable

* Refactor changelog view to handle missing avatars gracefully and improve session sign-out logic in tests

* Enhance changelog view to display fallback messages for unavailable release notes and publication dates

* Update onboarding system tests to reflect UI changes and improve assertions

- Changed button labels from "Get started" to "Continue" and "Complete" to align with updated UI.
- Updated text assertions for clarity, changing "Set your preferences" to "Configure your preferences".
- Adjusted locale selection options to include language codes.
- Enhanced validation error handling in preferences form.
- Improved navigation assertions to ensure accurate path checks.

test/controllers/pages_controller_test.rb

@@ -16,4 +16,35 @@ class PagesControllerTest < ActionDispatch::IntegrationTest
       assert_response :ok
     end
   end
+
+  test "changelog with nil release notes" do
+    # Mock the GitHub provider to return nil (simulating API failure or no releases)
+    github_provider = mock
+    github_provider.expects(:fetch_latest_release_notes).returns(nil)
+    Provider::Registry.stubs(:get_provider).with(:github).returns(github_provider)
+
+    get changelog_path
+    assert_response :ok
+    assert_select "h2", text: "Release notes unavailable"
+    assert_select "a[href='https://github.com/maybe-finance/maybe/releases']"
+  end
+
+  test "changelog with incomplete release notes" do
+    # Mock the GitHub provider to return incomplete data (missing some fields)
+    github_provider = mock
+    incomplete_data = {
+      avatar: nil,
+      username: "maybe-finance",
+      name: "Test Release",
+      published_at: nil,
+      body: nil
+    }
+    github_provider.expects(:fetch_latest_release_notes).returns(incomplete_data)
+    Provider::Registry.stubs(:get_provider).with(:github).returns(github_provider)
+
+    get changelog_path
+    assert_response :ok
+    assert_select "h2", text: "Test Release"
+    # Should not crash even with nil values
+  end
 end