Move Settings to Dashboard toolbar to kill iPhone More overflow

Six tabs forced iPhone to spill Course into the system "More" tab, whose
own NavigationStack nested with CourseView's and produced a double back
chevron on every week/deck push. Drop the Settings tab, reach it from a
gear button on Dashboard that presents SettingsView as a sheet, and keep
the visible tab count at five so no More overflow exists.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Conjuga/Conjuga/Views/Dashboard/DashboardView.swift

@@ -8,6 +8,7 @@ struct DashboardView: View {
     @State private var dailyLogs: [DailyLog] = []
     @State private var testResults: [TestResult] = []
     @State private var reviewCards: [ReviewCard] = []
+    @State private var showingSettings = false
 
     private var cloudModelContext: ModelContext { cloudModelContextProvider() }
 
@@ -33,6 +34,19 @@ struct DashboardView: View {
                 .adaptiveContainer(maxWidth: 800)
             }
             .navigationTitle("Dashboard")
+            .toolbar {
+                ToolbarItem(placement: .topBarTrailing) {
+                    Button {
+                        showingSettings = true
+                    } label: {
+                        Image(systemName: "gearshape")
+                    }
+                    .accessibilityLabel("Settings")
+                }
+            }
+            .sheet(isPresented: $showingSettings) {
+                SettingsView()
+            }
             .onAppear(perform: loadData)
         }
     }

Conjuga/Conjuga/Views/MainTabView.swift

@@ -18,9 +18,6 @@ struct MainTabView: View {
             Tab("Course", systemImage: "list.clipboard") {
                 CourseView()
             }
-            Tab("Settings", systemImage: "gearshape") {
-                SettingsView()
-            }
         }
     }
 }