feat: unify iOS/macOS navigation as NavigationSplitView, fix VM lifecycle

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WYqycDFsynHH9VnnK7LNSf

MyPass/ContentView.swift

@@ -19,7 +19,7 @@ struct ContentView: View {
             if session.isLocked {
                 UnlockView(vm: UnlockViewModel(session: session))
             } else {
-                vaultView
+                VaultRootView(session: session)
             }
         }
         .onReceive(
@@ -29,20 +29,6 @@ struct ContentView: View {
         }
     }
 
-    @ViewBuilder
-    private var vaultView: some View {
-        let vaultVM = VaultViewModel(session: session)
-        #if os(macOS)
-        MacVaultView(vm: vaultVM)
-        #else
-        NavigationStack {
-            if let root = session.database?.root {
-                GroupBrowserView(vm: vaultVM, group: root)
-            }
-        }
-        #endif
-    }
-
     private var sceneBackgroundNotification: Notification.Name {
         #if os(iOS)
         UIScene.didEnterBackgroundNotification
@@ -52,82 +38,41 @@ struct ContentView: View {
     }
 }
 
-// MARK: - macOS 3-column layout
+/// Owns the vault/group-filter view models for as long as the vault stays unlocked -- their
+/// state (search query, group filter selection) persists across re-renders but resets if the
+/// vault locks and is unlocked again (a fresh VaultRootView is created), which matches the
+/// expected "locking clears your filter" behavior.
+private struct VaultRootView: View {
+    @StateObject private var vaultVM: VaultViewModel
+    @StateObject private var filterVM: GroupFilterViewModel
+    @State private var columnVisibility: NavigationSplitViewVisibility = .all
 
-#if os(macOS)
-private struct MacVaultView: View {
-    @ObservedObject var vm: VaultViewModel
-    @State private var selectedGroup: MyPassCore.Group?
-    @State private var selectedEntry: Entry?
-    @State private var showAddEntry = false
-
-    private var activeGroup: MyPassCore.Group? { selectedGroup ?? vm.session.database?.root }
+    init(session: VaultSession) {
+        _vaultVM = StateObject(wrappedValue: VaultViewModel(session: session))
+        _filterVM = StateObject(wrappedValue: GroupFilterViewModel(session: session))
+    }
 
     var body: some View {
-        NavigationSplitView {
-            GroupSidebarView(vm: vm, selectedGroup: $selectedGroup)
-        } content: {
-            if vm.isSearching {
-                SearchView(vm: vm, selectedEntry: $selectedEntry)
-            } else if let group = activeGroup {
-                entryList(for: group)
-            } else {
-                Text("Select a group").foregroundStyle(.secondary)
+        NavigationSplitView(columnVisibility: $columnVisibility) {
+            if let root = vaultVM.session.database?.root {
+                GroupFilterView(vm: filterVM, rootGroup: root)
             }
         } detail: {
-            if let entry = selectedEntry {
-                EntryDetailView(entry: entry, session: vm.session)
-            } else {
-                Text("Select an entry").foregroundStyle(.secondary)
+            NavigationStack {
+                EntryListView(vm: vaultVM)
+                    .toolbar {
+                        ToolbarItem(placement: .navigation) {
+                            Button {
+                                columnVisibility = columnVisibility == .all ? .detailOnly : .all
+                            } label: {
+                                Image(systemName: "line.3.horizontal")
+                            }
+                        }
+                    }
             }
         }
-        .searchable(text: $vm.searchQuery, prompt: "Search all entries…")
-        .sheet(isPresented: $showAddEntry) {
-            if let group = activeGroup {
-                EntryEditView(vm: EntryEditViewModel(session: vm.session, groupId: group.id))
-            }
-        }
-    }
-
-    private func entryList(for group: MyPassCore.Group) -> some View {
-        List(group.entries, selection: $selectedEntry) { entry in
-            EntryListRow(entry: entry).tag(entry)
-        }
-        .navigationTitle(group.name)
-        .toolbar {
-            ToolbarItem {
-                Button { showAddEntry = true } label: { Image(systemName: "plus") }
-            }
+        .onChange(of: filterVM.selectedGroupIds) { _, newValue in
+            vaultVM.selectedGroupIds = newValue
         }
     }
 }
-
-private struct GroupSidebarView: View {
-    @ObservedObject var vm: VaultViewModel
-    @Binding var selectedGroup: MyPassCore.Group?
-
-    var body: some View {
-        List(selection: $selectedGroup) {
-            if let root = vm.session.database?.root {
-                GroupNode(group: root)
-            }
-        }
-        .navigationTitle("Groups")
-    }
-}
-
-private struct GroupNode: View {
-    let group: MyPassCore.Group
-    var body: some View {
-        if group.subgroups.isEmpty {
-            Label(group.name, systemImage: "folder").tag(group)
-        } else {
-            DisclosureGroup {
-                ForEach(group.subgroups) { sub in GroupNode(group: sub) }
-            } label: {
-                Label(group.name, systemImage: "folder").tag(group)
-            }
-        }
-    }
-}
-#endif