ios: full feature/appearance parity with the macOS app (client-side)

Port the Mac's MarkdownText renderer, AppPalette (color-vision modes +
night-softening), appearance settings (theme/text size/color vision),
and BuildBanner channel strip to the iPhone remote. Add session-row
attention/unseen-completion washes and marker icons, Discard action,
branch/worktree options in the new-chat composer, and a transient
error bubble for host wire errors. Stamp the build channel via
NucleicChannel in Info.plist (ios-release.sh passes NUCLEIC_CHANNEL,
default beta). Demo mode gains NUCLEIC_DEMO_SESSION and skips the
notifications prompt so UI previews are scriptable.

Co-Authored-By: Claude Fable 5 <[email protected]>

NucleicRemote/NucleicRemote/Views/Composer.swift

@@ -10,6 +10,10 @@ struct StartChatComposer: View {
     @State private var auto = false
     @State private var model: String?
     @State private var effort = MobileEfforts.fallback
+    // Advanced options (the Mac new-session sheet's base branch + worktree fields).
+    @State private var showOptions = false
+    @State private var baseBranch = ""
+    @State private var useWorktree = true
 
     private var projects: [WireProject] { store.dashboard.projects }
     private var selected: WireProject? {
@@ -42,6 +46,32 @@ struct StartChatComposer: View {
                 ModelMenu(model: $model, catalog: store.modelCatalog, backend: nil)
                 Spacer()
                 EffortMenu(effort: $effort, catalog: store.modelCatalog, modelSKU: model, controlled: controlled)
+                Button {
+                    withAnimation(.easeInOut(duration: 0.18)) { showOptions.toggle() }
+                } label: {
+                    Image(systemName: showOptions ? "chevron.up.circle" : "ellipsis.circle")
+                        .font(.caption)
+                        .foregroundStyle(Palette.accent)
+                }
+                .buttonStyle(.plain)
+            }
+            if showOptions {
+                VStack(alignment: .leading, spacing: 8) {
+                    HStack(spacing: 8) {
+                        Image(systemName: "arrow.triangle.branch").foregroundStyle(.secondary)
+                        TextField(selected?.defaultBranch ?? "Base branch", text: $baseBranch)
+                            .textInputAutocapitalization(.never)
+                            .autocorrectionDisabled()
+                            .textFieldStyle(.roundedBorder)
+                            .font(.caption)
+                    }
+                    Toggle(isOn: $useWorktree) {
+                        Label("Run in a worktree", systemImage: "square.stack.3d.up")
+                            .font(.caption)
+                    }
+                    .tint(Palette.accent)
+                }
+                .transition(.move(edge: .top).combined(with: .opacity))
             }
             HStack(alignment: .bottom, spacing: 8) {
                 TextField("Describe a task…", text: $draft, axis: .vertical)
@@ -51,7 +81,11 @@ struct StartChatComposer: View {
                     .keyboardDismissable()
                 Button {
                     if let project = selected {
-                        store.startChat(in: project.id, message: draft, model: model, effort: effort, auto: auto)
+                        let branch = baseBranch.trimmingCharacters(in: .whitespaces)
+                        store.startChat(
+                            in: project.id, message: draft, model: model, effort: effort,
+                            baseBranch: branch.isEmpty ? nil : branch,
+                            useWorktree: useWorktree, auto: auto)
                         draft = ""
                     }
                 } label: {