fix(account): Anmelden-Button + ManaAuthGate-Wiring

AccountView hatte zwar einen Status-Text aber keinen Login-Button,
und der ManaAuthGate war überhaupt nicht im App-Tree eingebaut —
Guest-Mode-User konnten sich nirgends anmelden.

- ZitareNativeApp: ManaAuthGate(auth:) instantiiert + via environment
  durchgereicht
- RootView: .manaBrand(ZitareBrand.manaBrand) +
  .manaAuthGate(authGate) { ManaLoginView(…) } für globales
  Sign-In-Sheet
- AccountView: authActionCard mit "Mit mana-Konto anmelden" /
  "Abmelden" (keepGuestMode: true)
- ZitareBrand neu (paper-Theme-Brücke zu ManaBrandConfig)
- project.yml: platformFilter: iOS für Widget+Share-Extensions
  (macOS-Build war pre-existing kaputt mit "embedded iOS content")

iOS + macOS BUILD SUCCEEDED.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Sources/App/RootView.swift

@@ -1,3 +1,4 @@
+import ManaAuthUI
 import ManaCore
 import ManaWebShell
 import SwiftUI
@@ -43,6 +44,7 @@ private func makeWebShellConfig() -> WebShellConfig {
 /// die App und routen in den passenden Tab.
 struct RootView: View {
     @Environment(AuthClient.self) private var auth
+    @Environment(ManaAuthGate.self) private var authGate
     @State private var selectedTab: AppTab = .read
     @State private var readTarget = WebTarget(url: AppConfig.webBaseURL)
     @State private var exploreTarget = WebTarget(
@@ -76,6 +78,17 @@ struct RootView: View {
             .toolbarBackground(ZitareTheme.background, for: .windowToolbar)
             .toolbarBackground(.visible, for: .windowToolbar)
         #endif
+        .manaBrand(ZitareBrand.manaBrand)
+        .manaAuthGate(authGate) {
+            NavigationStack {
+                ManaLoginView(
+                    auth: auth,
+                    onSignUpTapped: {},
+                    onForgotTapped: {}
+                )
+                .manaBrand(ZitareBrand.manaBrand)
+            }
+        }
         .task {
             await probeHealth()
         }

Sources/App/ZitareNativeApp.swift

@@ -1,3 +1,4 @@
+import ManaAuthUI
 import ManaCore
 import SwiftData
 import SwiftUI
@@ -6,12 +7,14 @@ import WidgetKit
 @main
 struct ZitareNativeApp: App {
     @State private var auth: AuthClient
+    @State private var authGate: ManaAuthGate
     private let snapshotContainer: ModelContainer?
 
     init() {
         let auth = AuthClient(config: AppConfig.manaAppConfig)
         auth.bootstrap()
         _auth = State(initialValue: auth)
+        _authGate = State(initialValue: ManaAuthGate(auth: auth))
         do {
             snapshotContainer = try SnapshotContainer.make()
         } catch {
@@ -29,6 +32,7 @@ struct ZitareNativeApp: App {
         WindowGroup {
             RootView()
                 .environment(auth)
+                .environment(authGate)
                 .tint(ZitareTheme.primary)
                 .task {
                     await refreshSnapshot()

Sources/Core/Theme/ZitareBrand.swift

@@ -0,0 +1,21 @@
+import ManaAuthUI
+
+/// Brücke zwischen `ZitareTheme` (paper-Variant) und der
+/// `ManaBrandConfig` von `ManaAuthUI`. Im App-Body als Environment-Wert
+/// gesetzt — Login-Sheet bekommt damit das paper-Theme statt mana-Default.
+enum ZitareBrand {
+    static let manaBrand = ManaBrandConfig(
+        appName: "Zitare",
+        tagline: "Öffentlicher Zitat-Korpus von mana e.V.",
+        logoSymbol: "quote.opening",
+        background: ZitareTheme.background,
+        foreground: ZitareTheme.foreground,
+        surface: ZitareTheme.surface,
+        mutedForeground: ZitareTheme.mutedForeground,
+        border: ZitareTheme.border,
+        primary: ZitareTheme.primary,
+        primaryForeground: ZitareTheme.primaryForeground,
+        error: ZitareTheme.error,
+        success: ZitareTheme.success
+    )
+}

Sources/Features/Account/AccountView.swift

@@ -1,13 +1,21 @@
+import ManaAuthUI
 import ManaCore
 import SwiftUI
 
 /// Phase ζ-0 minimal: zeigt Auth-Status und Healthz-Probe-Ergebnis.
-/// Phase ζ-3 erweitert um ManaAuthUI-Login-Sheet und Submission-
-/// History-Link (via WebShell auf `zitare.mana.how/me`).
+/// Phase ζ-3 erweitert um Submission-History-Link (via WebShell auf
+/// `zitare.mana.how/me`). Login-Sheet schon hier, damit Guests einen
+/// Anmelden-Button finden.
 struct AccountView: View {
     @Environment(AuthClient.self) private var auth
+    @Environment(ManaAuthGate.self) private var authGate
     let healthStatus: HealthStatus
 
+    private var isSignedIn: Bool {
+        if case .signedIn = auth.status { return true }
+        return false
+    }
+
     var body: some View {
         ScrollView {
             VStack(spacing: 24) {
@@ -15,6 +23,8 @@ struct AccountView: View {
 
                 statusCard
 
+                authActionCard
+
                 Spacer(minLength: 32)
 
                 aboutCard
@@ -25,6 +35,30 @@ struct AccountView: View {
         .background(ZitareTheme.background)
     }
 
+    @ViewBuilder
+    private var authActionCard: some View {
+        if isSignedIn {
+            Button(role: .destructive) {
+                Task { await auth.signOut(keepGuestMode: true) }
+            } label: {
+                Label("Abmelden", systemImage: "arrow.left.square")
+                    .frame(maxWidth: .infinity)
+            }
+            .buttonStyle(.bordered)
+            .controlSize(.large)
+        } else {
+            Button {
+                authGate.isPresentingSignIn = true
+            } label: {
+                Label("Mit mana-Konto anmelden", systemImage: "arrow.right.square")
+                    .frame(maxWidth: .infinity)
+            }
+            .buttonStyle(.borderedProminent)
+            .controlSize(.large)
+            .tint(ZitareTheme.primary)
+        }
+    }
+
     private var header: some View {
         VStack(spacing: 12) {
             // Eigenes Anführungszeichen-Glyph in der gleichen Variante