fix(apple/tvOS): pushed routes instead of modal covers — the Settings-app navigation feel

Add Host, Settings and PIN pairing were fullScreenCover overlays, which is why
navigating felt unlike the system Settings app (no push animation, no Menu-pops-a-level
semantics). They are now navigationDestination ROUTES pushed inside the home
NavigationStack:

- the system push/pop animation and Menu-button back navigation come for free;
- the Settings pickers' navigationLink pushes reuse the same stack (its inner
  NavigationStack wrapper is gone, as is the tvOS Done row — Menu pops, like Settings);
- Add Host is a real full-screen page (system navigation title, Settings-style rows on
  the standard backdrop) instead of a floating dialog, same for the pairing page;
- the thickMaterial cover backdrops became unnecessary and are gone. The system
  keyboard entries stay as covers — that presentation is system-owned either way.

iOS/macOS keep their sheets. Verified by screenshot: Add Host renders as a pushed
full-screen route with the title top-center.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

clients/apple/Sources/PunktfunkClient/AddHostSheet.swift

@@ -23,8 +23,6 @@ struct AddHostSheet: View {
         // No inline text editing on tvOS — Settings-style value rows; pressing one
         // raises the SYSTEM fullscreen keyboard (TVTextEntry).
         VStack(spacing: 24) {
-            Text("Add Host")
-                .font(.title3.weight(.semibold))
             TVFieldRow(
                 label: "Name", value: name, placeholder: "Optional"
             ) { editing = .name }
@@ -43,6 +41,7 @@ struct AddHostSheet: View {
         }
         .frame(maxWidth: 1000)
         .padding(60)
+        .navigationTitle("Add Host")
         .fullScreenCover(item: $editing) { field in
             switch field {
             case .name:

clients/apple/Sources/PunktfunkClient/ContentView.swift

@@ -55,18 +55,7 @@ struct ContentView: View {
         // On the outer Group so the sheet survives the trust-prompt → home transition
         // (the "Pair with PIN instead" path disconnects first — the host's accept loop
         // is sequential, a pairing connection would queue behind the live session).
-        #if os(tvOS)
-        .fullScreenCover(item: $pairingTarget) { host in
-            PairSheet(host: host) { fingerprint in
-                guard pairingTarget?.id == host.id else { return }
-                store.pin(host.id, fingerprint: fingerprint)
-                var pinned = host
-                pinned.pinnedSHA256 = fingerprint
-                connect(pinned)
-            }
-            .background(.thickMaterial, ignoresSafeAreaEdges: .all)
-        }
-        #else
+        #if !os(tvOS)
         .sheet(item: $pairingTarget) { host in
             PairSheet(host: host) { fingerprint in
                 // Backstop against a stale ceremony surfacing after dismissal (PairSheet
@@ -149,6 +138,25 @@ struct ContentView: View {
                 }
             }
             .navigationTitle("Punktfunkempfänger")
+            #if os(tvOS)
+            // Pushed routes — the Settings-app navigation feel (push animation, Menu
+            // pops) instead of modal overlays.
+            .navigationDestination(isPresented: $showAddHost) {
+                AddHostSheet { store.add($0) }
+            }
+            .navigationDestination(isPresented: $showSettings) {
+                SettingsView()
+            }
+            .navigationDestination(item: $pairingTarget) { host in
+                PairSheet(host: host) { fingerprint in
+                    guard pairingTarget?.id == host.id else { return }
+                    store.pin(host.id, fingerprint: fingerprint)
+                    var pinned = host
+                    pinned.pinnedSHA256 = fingerprint
+                    connect(pinned)
+                }
+            }
+            #endif
             #if !os(tvOS)
             .toolbar {
                 #if os(iOS)
@@ -173,20 +181,7 @@ struct ContentView: View {
         #if os(macOS)
         .frame(minWidth: 480, minHeight: 360)
         #endif
-        #if os(tvOS)
-        // tvOS forms/lists have CLEAR backgrounds and a cover only shows what the
-        // presented view paints — back them with the standard tv blur-over-content.
-        .fullScreenCover(isPresented: $showAddHost) {
-            AddHostSheet { store.add($0) }
-                .background(.thickMaterial, ignoresSafeAreaEdges: .all)
-        }
-        .fullScreenCover(isPresented: $showSettings) {
-            NavigationStack {
-                SettingsView()
-            }
-            .background(.thickMaterial, ignoresSafeAreaEdges: .all)
-        }
-        #else
+        #if !os(tvOS)
         .sheet(isPresented: $showAddHost) {
             AddHostSheet { store.add($0) }
         }

clients/apple/Sources/PunktfunkClient/PairSheet.swift

@@ -44,9 +44,6 @@ struct PairSheet: View {
     var body: some View {
         #if os(tvOS)
         VStack(spacing: 24) {
-            Label("Pair with \(host.displayName)", systemImage: "lock.shield")
-                .font(.title3.weight(.semibold))
-                .foregroundStyle(.tint)
             Text("The host prints the PIN when pairing is armed "
                 + "(--allow-pairing, \u{201C}PAIRING ARMED\u{201D} in its log). "
                 + "Pairing verifies both sides at once — no fingerprint comparison "
@@ -80,6 +77,7 @@ struct PairSheet: View {
         }
         .frame(maxWidth: 1000)
         .padding(60)
+        .navigationTitle("Pair with \(host.displayName)")
         .onDisappear { token.cancelled = true }
         .fullScreenCover(item: $editing) { field in
             switch field {

clients/apple/Sources/PunktfunkClient/SettingsView.swift

@@ -87,9 +87,6 @@ struct SettingsView: View {
                     .font(.caption)
                     .foregroundStyle(.secondary)
             }
-            Section {
-                Button("Done") { dismiss() }
-            }
         }
         .navigationTitle("Settings")
     }