Slim bottom tab bar to Apple height; remove redundant reload button; bump to 2.4

- Bottom tab bar: reduce vertical padding (8→4), icon size (20→18), and
  bottom inset (8→4) so it matches Apple's standard compact tab bar height
  (Apple Music etc.) instead of a tall bar.
- Remove the manual reload button from the loaded PR toolbar — the detail
  view auto-loads on appearance, so it was redundant clutter. The reload
  button is kept only on the error/retry state. Bump to 2.4.

GiteaPR/Detail/PRDetailView.swift

@@ -100,7 +100,6 @@ struct PRDetailView: View {
             bottomTabBar
         }
         .toolbar {
-            ToolbarItem(placement: .primaryAction) { reloadButton }
             if prIsOpen {
                 ToolbarItem(placement: .primaryAction) { mergeButton }
                 ToolbarItem(placement: .primaryAction) { reviewMenu }
@@ -132,17 +131,17 @@ struct PRDetailView: View {
     }
 
     /// Bottom tab bar: icon-only navigation between the PR's sections, in a
-    /// floating capsule style (like the latest iOS tab bars) rather than a
-    /// full-width bar.
+    /// compact floating capsule style matching Apple's standard tab bar
+    /// height (Apple Music etc.), not a tall bar.
     private var bottomTabBar: some View {
         HStack {
             ForEach(DetailTab.allCases) { tab in
                 Button {
                     selectedTab = tab
                 } label: {
-                    VStack(spacing: 2) {
+                    VStack(spacing: 1) {
                         Image(systemName: tab.icon)
-                            .font(.system(size: 20))
+                            .font(.system(size: 18))
                         Text(tab.rawValue)
                             .font(.caption2)
                     }
@@ -151,15 +150,15 @@ struct PRDetailView: View {
                 }
             }
         }
-        .padding(.vertical, 8)
+        .padding(.vertical, 4)
         .padding(.horizontal, 6)
         .background(
             Capsule()
                 .fill(.regularMaterial)
-                .shadow(color: .black.opacity(0.15), radius: 8, y: 2)
+                .shadow(color: .black.opacity(0.12), radius: 6, y: 1)
         )
         .padding(.horizontal, 16)
-        .padding(.bottom, 8)
+        .padding(.bottom, 4)
     }
 
     private var reviewMenu: some View {