fix(theme): resolve nav/login kit issues + bump 0.2.1 -> 0.3.0

Addresses ZB.MOM.WW.Theme/themeissues.md:
- #1 NavRailSection <summary> renders aria-expanded (SSR from Expanded),
  kept in sync by nav-state.js on restore + toggle.
- #2 nav-state.js auto-expands the section holding a.rail-link.active
  (transient via data-zbnav-transient — does not overwrite saved state).
- #3 nav-state.js re-applies on Blazor 'enhancedload' (idempotent via
  per-element init guard).
- #5 LoginCard wraps product in span.login-product + optional Heading
  override param.
- #4 documented as an accepted client-only-persistence tradeoff (no code change).

+4 bUnit tests (48 total, all green).

ZB.MOM.WW.Theme/tests/ZB.MOM.WW.Theme.Tests/NavRailTests.cs

@@ -47,6 +47,17 @@ public class NavRailTests : TestContext
         Assert.NotNull(cut.Find(".rail-section-body .rail-link"));
     }
 
+    // Theme issue #1: the <summary> mirrors the <details open> state via
+    // aria-expanded so tests and assistive tech have a stable, queryable attribute.
+    [Fact]
+    public void NavRailSection_summary_aria_expanded_true_when_open()
+    {
+        var cut = RenderComponent<NavRailSection>(p => p
+            .Add(x => x.Title, "Navigation")
+            .AddChildContent("<a class='rail-link'>X</a>"));
+        Assert.Equal("true", cut.Find("summary.rail-eyebrow-toggle").GetAttribute("aria-expanded"));
+    }
+
     [Fact]
     public void NavRailSection_collapsed_when_not_expanded()
     {
@@ -56,6 +67,16 @@ public class NavRailTests : TestContext
         Assert.False(cut.Find("details.rail-section").HasAttribute("open"));
     }
 
+    // Theme issue #1: aria-expanded reflects the collapsed SSR state too.
+    [Fact]
+    public void NavRailSection_summary_aria_expanded_false_when_collapsed()
+    {
+        var cut = RenderComponent<NavRailSection>(p => p
+            .Add(x => x.Title, "Nav").Add(x => x.Expanded, false)
+            .AddChildContent("<a class='rail-link'>X</a>"));
+        Assert.Equal("false", cut.Find("summary.rail-eyebrow-toggle").GetAttribute("aria-expanded"));
+    }
+
     [Fact]
     public void NavRailSection_emits_data_nav_key_slug_from_title_by_default()
     {