fix(ios): keep active chat, sidebar + Settings sheet across settings changes

ios/TaskWraithKit/Sources/TaskWraithUI/AppShell.swift

@@ -77,6 +77,16 @@ public struct RootView: View {
         // Theme tokens are computed statics — a revision bump rebuilds the
         // tree so every TWTheme read picks up the new selection.
         .id(themes.revision)
+        // Settings sheet lives ABOVE the revision teardown (attached after
+        // `.id`) so a theme/composer/font change made inside it keeps the sheet
+        // open — AppSettingsSheet re-themes live via its own @ObservedObject
+        // themes. Presented here, not from HomeView, which is inside the
+        // `.id(revision)` subtree that rebuilds on every settings change.
+        .sheet(isPresented: $model.settingsPresented) {
+            AppSettingsSheet()
+                .presentationDetents([.medium, .large])
+                .presentationDragIndicator(.visible)
+        }
         .animation(.easeInOut(duration: 0.25), value: showShellDuringDrop)
         // Privacy shield: iOS snapshots the UI for the app switcher —
         // transcripts and file contents must not be readable there.
@@ -176,7 +186,6 @@ struct MastheadRow: View {
 struct ConnectedShell: View {
     @ObservedObject var model: RemoteSessionModel
     @Environment(\.horizontalSizeClass) private var sizeClass
-    @State private var selectedTaskId: String?
     @StateObject private var fileState = MobileFileEditorState()
     @StateObject private var diffState = MobileDiffStudioState()
     @State private var shellMode: ShellMode = .app
@@ -232,11 +241,11 @@ struct ConnectedShell: View {
                 }
             } else {
                 NavigationSplitView {
-                    HomeView(model: model, selection: $selectedTaskId, explicitSelection: true)
+                    HomeView(model: model, selection: $model.selectedTaskId, explicitSelection: true)
                         .navigationSplitViewColumnWidth(min: 300, ideal: 340)
                         .iPadSidebarInnerRim(edge: .trailing)
                 } detail: {
-                    if let taskId = selectedTaskId, taskId.hasPrefix("new-") {
+                    if let taskId = model.selectedTaskId, taskId.hasPrefix("new-") {
                         NavigationStack {
                             NewChatBootstrapView(
                                 model: model,
@@ -247,7 +256,7 @@ struct ConnectedShell: View {
                                     ? String(taskId.split(separator: ":")[1]) : nil)
                         }
                         .id(taskId)
-                    } else if let taskId = selectedTaskId {
+                    } else if let taskId = model.selectedTaskId {
                         // Hand-rolled third column: SwiftUI's `.inspector`
                         // presents as an overlay here regardless of attach
                         // level (tried both); an HStack pane DETERMINISTICALLY
@@ -259,7 +268,7 @@ struct ConnectedShell: View {
                             if model.inspectorPresented {
                                 ThreadInspector(model: model, threadId: taskId) { childId in
                                     model.inspectorPresented = false
-                                    selectedTaskId = childId
+                                    model.selectedTaskId = childId
                                 }
                                 .frame(width: 390)
                                 .background(TWTheme.appBg)
@@ -281,8 +290,8 @@ struct ConnectedShell: View {
             }
         } else {
             NavigationStack {
-                HomeView(model: model, selection: $selectedTaskId)
-                    .navigationDestination(for: String.self) { taskId in
+                HomeView(model: model, selection: $model.selectedTaskId)
+                    .navigationDestination(item: $model.selectedTaskId) { taskId in
                         ThreadDetailView(model: model, taskId: taskId)
                             // Compact: the same binding presents as a sheet.
                             .inspector(isPresented: $model.inspectorPresented) {

ios/TaskWraithKit/Sources/TaskWraithUI/HomeListViews.swift

@@ -19,9 +19,12 @@ import TaskWraithKit
 struct HomeView: View {
     @ObservedObject var model: RemoteSessionModel
     @Binding var selection: String?
-    /// Parent chats whose sub-thread/side-chat children are collapsed.
-    @State private var collapsedParents: Set<String> = []
-    @State private var showSettings = false
+    /// Parent chats whose sub-thread/side-chat children are collapsed. Backed by
+    /// the model so it survives the theme-revision teardown (see selectedTaskId).
+    private var collapsedParents: Set<String> {
+        get { model.collapsedParents }
+        nonmutating set { model.collapsedParents = newValue }
+    }
     @State private var canvasMode: ComposeMode? = nil
 
     private func openCanvas(_ mode: ComposeMode) {
@@ -40,10 +43,16 @@ struct HomeView: View {
     /// Workspace folders the user has EXPANDED — inverted from the old
     /// collapsed-set so folders start collapsed (a tidy first open; expand
     /// state then sticks for the session).
-    @State private var expandedWorkspaces: Set<String> = []
+    private var expandedWorkspaces: Set<String> {
+        get { model.expandedWorkspaces }
+        nonmutating set { model.expandedWorkspaces = newValue }
+    }
     /// Top-level sections (activeRuns / pinned / recents / workspaces /
     /// globalChats) the user has collapsed — sections start expanded.
-    @State private var collapsedSections: Set<String> = []
+    private var collapsedSections: Set<String> {
+        get { model.collapsedSections }
+        nonmutating set { model.collapsedSections = newValue }
+    }
 
     /// Top-level threads per workspace; sub-threads/side chats nest under
     /// their parent like the desktop sidebar.
@@ -112,7 +121,7 @@ struct HomeView: View {
                         Image(systemName: "arrow.clockwise")
                     }
                     Button {
-                        showSettings = true
+                        model.settingsPresented = true
                     } label: {
                         Image(systemName: "gearshape")
                     }
@@ -128,11 +137,6 @@ struct HomeView: View {
         .navigationDestination(item: $canvasMode) { mode in
             NewChatBootstrapView(model: model, mode: mode, initialWorkspaceId: nil)
         }
-        .sheet(isPresented: $showSettings) {
-            AppSettingsSheet()
-                .presentationDetents([.medium, .large])
-                .presentationDragIndicator(.visible)
-        }
     }
 
     @ViewBuilder
@@ -488,9 +492,20 @@ struct HomeView: View {
             .listRowSeparator(.hidden)
             .listRowBackground(selectedChrome)
         } else {
-            NavigationLink(value: card.id) {
-                TaskRow(model: model, card: card, nested: nested)
+            // Compact: selection-driven push via `navigationDestination(item:)`
+            // (not NavigationLink) so the open chat is restorable from the
+            // model after the theme-revision teardown.
+            Button {
+                selection = card.id
+            } label: {
+                HStack(spacing: 6) {
+                    TaskRow(model: model, card: card, nested: nested)
+                    Image(systemName: "chevron.right")
+                        .font(.caption2)
+                        .foregroundStyle(TWTheme.textMuted)
+                }
             }
+            .buttonStyle(.plain)
             .listRowInsets(rowInsets)
             .listRowSeparator(.hidden)
             .listRowBackground(rowChrome)

ios/TaskWraithKit/Sources/TaskWraithUI/RemoteSessionModel.swift

@@ -207,6 +207,22 @@ public final class RemoteSessionModel: ObservableObject {
     @Published public private(set) var lastActionMessage: String?
     /// Set after createThread succeeds — HomeView navigates to the new chat.
     @Published public var navigationTarget: String?
+    /// The chat the user has open (sidebar selection / pushed thread), plus the
+    /// sidebar's expand/collapse layout. Hoisted onto the model so they SURVIVE
+    /// the theme-revision view teardown: TWThemeStore bumps `revision` on any
+    /// settings change and RootView keys `.id(revision)` (TWTheme tokens are
+    /// computed statics, so the rebuild is how they re-read) — which would
+    /// otherwise drop the open chat + reset the sidebar. `selectedTaskId` drives
+    /// the iPad detail column and the iPhone `navigationDestination(item:)`.
+    @Published public var selectedTaskId: String?
+    @Published public var expandedWorkspaces: Set<String> = []
+    @Published public var collapsedSections: Set<String> = []
+    @Published public var collapsedParents: Set<String> = []
+    /// Settings sheet presentation — hoisted so a theme/composer/font change
+    /// made inside it doesn't tear the sheet down with the rest of the tree.
+    /// Presented from RootView (above the `.id(revision)` boundary); the sheet
+    /// re-themes live via its own `@ObservedObject themes`.
+    @Published public var settingsPresented = false
     /// Deep-link target captured from a notification tap before the session is
     /// established (cold launch); applied to navigationTarget on `.established`.
     private var pendingDeepLinkThreadId: String?