feat(studio): guided-setup wizard (reuses chain init engine)

A Welcome 'Setup assistant' button opens a wizard that collects
scenario / intent / target (+ approval & data-local toggles), then calls
`chain init --answers` to preview the assembled plan and `--apply --force`
to write the config — reusing the Rust deterministic engine, no logic
duplicated. New SystemActions.chainInit; copyable errors via
showFaiProcessError; EN+DE l10n. analyze clean; smoke test + existing
welcome/sidebar tests pass.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

lib/data/system_actions.dart

@@ -143,6 +143,15 @@ class SystemActions {
     return _runFai(['daemon', ...args]);
   }
 
+  /// Run a `chain init ...` subcommand. Used by the guided-setup
+  /// wizard to preview a plan (`--answers <file>`) and apply it
+  /// (`--answers <file> --apply --force`).
+  static Future<({bool ok, String stdout, String stderr})> chainInit(
+    List<String> args,
+  ) async {
+    return _runFai(['init', ...args]);
+  }
+
   /// Run `chain update apply --channel <c>`. Long-running on a slow
   /// network — caller should show a spinner.
   static Future<({bool ok, String stdout, String stderr})> chainUpdateApply(

lib/l10n/app_de.arb

@@ -1,5 +1,19 @@
 {
   "@@locale": "de",
+  "guidedSetupTitle": "Setup-Assistent",
+  "guidedSetupIntro": "Beantworte drei Fragen — Ch∆In stellt passende Konfiguration, Modul-Set und Start-Flow zusammen.",
+  "guidedSetupScenario": "Szenario",
+  "guidedSetupIntent": "Aufgabe",
+  "guidedSetupTarget": "Wo läuft es?",
+  "guidedSetupApproval": "Menschlichen Freigabe-Schritt vor dem KI-Schritt verlangen",
+  "guidedSetupDataLocal": "Daten müssen lokal bleiben (air-gapped)",
+  "guidedSetupReviewHeading": "Diesen Plan wird Ch∆In anwenden:",
+  "guidedSetupApply": "Setup übernehmen",
+  "guidedSetupApplied": "Setup übernommen. Schließe mit den Schritten unten ab:",
+  "guidedSetupBack": "Zurück",
+  "guidedSetupNext": "Weiter",
+  "guidedSetupCancel": "Abbrechen",
+  "guidedSetupClose": "Schließen",
   "appTitle": "Ch∆In Studio",
   "navWelcome": "Willkommen",
   "welcomeHeroTitle": "Ch∆In Platform",

lib/l10n/app_en.arb

@@ -1,5 +1,19 @@
 {
   "@@locale": "en",
+  "guidedSetupTitle": "Setup assistant",
+  "guidedSetupIntro": "Answer three questions and Ch∆In assembles a tailored config, module set and starter flow.",
+  "guidedSetupScenario": "Scenario",
+  "guidedSetupIntent": "Task",
+  "guidedSetupTarget": "Where will it run?",
+  "guidedSetupApproval": "Require a human approval step before the AI step",
+  "guidedSetupDataLocal": "Data must stay local (air-gapped posture)",
+  "guidedSetupReviewHeading": "This is the plan Ch∆In will apply:",
+  "guidedSetupApply": "Apply setup",
+  "guidedSetupApplied": "Setup applied. Finish with the steps below:",
+  "guidedSetupBack": "Back",
+  "guidedSetupNext": "Next",
+  "guidedSetupCancel": "Cancel",
+  "guidedSetupClose": "Close",
   "appTitle": "Ch∆In Studio",
   "@appTitle": {
     "description": "App-bar title in the OS task switcher."

lib/l10n/app_localizations.dart

@@ -98,6 +98,90 @@ abstract class AppLocalizations {
     Locale('en'),
   ];
 
+  /// No description provided for @guidedSetupTitle.
+  ///
+  /// In en, this message translates to:
+  /// **'Setup assistant'**
+  String get guidedSetupTitle;
+
+  /// No description provided for @guidedSetupIntro.
+  ///
+  /// In en, this message translates to:
+  /// **'Answer three questions and Ch∆In assembles a tailored config, module set and starter flow.'**
+  String get guidedSetupIntro;
+
+  /// No description provided for @guidedSetupScenario.
+  ///
+  /// In en, this message translates to:
+  /// **'Scenario'**
+  String get guidedSetupScenario;
+
+  /// No description provided for @guidedSetupIntent.
+  ///
+  /// In en, this message translates to:
+  /// **'Task'**
+  String get guidedSetupIntent;
+
+  /// No description provided for @guidedSetupTarget.
+  ///
+  /// In en, this message translates to:
+  /// **'Where will it run?'**
+  String get guidedSetupTarget;
+
+  /// No description provided for @guidedSetupApproval.
+  ///
+  /// In en, this message translates to:
+  /// **'Require a human approval step before the AI step'**
+  String get guidedSetupApproval;
+
+  /// No description provided for @guidedSetupDataLocal.
+  ///
+  /// In en, this message translates to:
+  /// **'Data must stay local (air-gapped posture)'**
+  String get guidedSetupDataLocal;
+
+  /// No description provided for @guidedSetupReviewHeading.
+  ///
+  /// In en, this message translates to:
+  /// **'This is the plan Ch∆In will apply:'**
+  String get guidedSetupReviewHeading;
+
+  /// No description provided for @guidedSetupApply.
+  ///
+  /// In en, this message translates to:
+  /// **'Apply setup'**
+  String get guidedSetupApply;
+
+  /// No description provided for @guidedSetupApplied.
+  ///
+  /// In en, this message translates to:
+  /// **'Setup applied. Finish with the steps below:'**
+  String get guidedSetupApplied;
+
+  /// No description provided for @guidedSetupBack.
+  ///
+  /// In en, this message translates to:
+  /// **'Back'**
+  String get guidedSetupBack;
+
+  /// No description provided for @guidedSetupNext.
+  ///
+  /// In en, this message translates to:
+  /// **'Next'**
+  String get guidedSetupNext;
+
+  /// No description provided for @guidedSetupCancel.
+  ///
+  /// In en, this message translates to:
+  /// **'Cancel'**
+  String get guidedSetupCancel;
+
+  /// No description provided for @guidedSetupClose.
+  ///
+  /// In en, this message translates to:
+  /// **'Close'**
+  String get guidedSetupClose;
+
   /// App-bar title in the OS task switcher.
   ///
   /// In en, this message translates to:

lib/l10n/app_localizations_de.dart

@@ -8,6 +8,51 @@ import 'app_localizations.dart';
 class AppLocalizationsDe extends AppLocalizations {
   AppLocalizationsDe([String locale = 'de']) : super(locale);
 
+  @override
+  String get guidedSetupTitle => 'Setup-Assistent';
+
+  @override
+  String get guidedSetupIntro =>
+      'Beantworte drei Fragen — Ch∆In stellt passende Konfiguration, Modul-Set und Start-Flow zusammen.';
+
+  @override
+  String get guidedSetupScenario => 'Szenario';
+
+  @override
+  String get guidedSetupIntent => 'Aufgabe';
+
+  @override
+  String get guidedSetupTarget => 'Wo läuft es?';
+
+  @override
+  String get guidedSetupApproval =>
+      'Menschlichen Freigabe-Schritt vor dem KI-Schritt verlangen';
+
+  @override
+  String get guidedSetupDataLocal => 'Daten müssen lokal bleiben (air-gapped)';
+
+  @override
+  String get guidedSetupReviewHeading => 'Diesen Plan wird Ch∆In anwenden:';
+
+  @override
+  String get guidedSetupApply => 'Setup übernehmen';
+
+  @override
+  String get guidedSetupApplied =>
+      'Setup übernommen. Schließe mit den Schritten unten ab:';
+
+  @override
+  String get guidedSetupBack => 'Zurück';
+
+  @override
+  String get guidedSetupNext => 'Weiter';
+
+  @override
+  String get guidedSetupCancel => 'Abbrechen';
+
+  @override
+  String get guidedSetupClose => 'Schließen';
+
   @override
   String get appTitle => 'Ch∆In Studio';
 

lib/l10n/app_localizations_en.dart

@@ -8,6 +8,52 @@ import 'app_localizations.dart';
 class AppLocalizationsEn extends AppLocalizations {
   AppLocalizationsEn([String locale = 'en']) : super(locale);
 
+  @override
+  String get guidedSetupTitle => 'Setup assistant';
+
+  @override
+  String get guidedSetupIntro =>
+      'Answer three questions and Ch∆In assembles a tailored config, module set and starter flow.';
+
+  @override
+  String get guidedSetupScenario => 'Scenario';
+
+  @override
+  String get guidedSetupIntent => 'Task';
+
+  @override
+  String get guidedSetupTarget => 'Where will it run?';
+
+  @override
+  String get guidedSetupApproval =>
+      'Require a human approval step before the AI step';
+
+  @override
+  String get guidedSetupDataLocal =>
+      'Data must stay local (air-gapped posture)';
+
+  @override
+  String get guidedSetupReviewHeading => 'This is the plan Ch∆In will apply:';
+
+  @override
+  String get guidedSetupApply => 'Apply setup';
+
+  @override
+  String get guidedSetupApplied =>
+      'Setup applied. Finish with the steps below:';
+
+  @override
+  String get guidedSetupBack => 'Back';
+
+  @override
+  String get guidedSetupNext => 'Next';
+
+  @override
+  String get guidedSetupCancel => 'Cancel';
+
+  @override
+  String get guidedSetupClose => 'Close';
+
   @override
   String get appTitle => 'Ch∆In Studio';
 

lib/pages/welcome.dart

@@ -19,6 +19,7 @@ import '../l10n/app_localizations.dart';
 import '../main.dart' show StudioShellState;
 import '../theme/theme.dart';
 import '../theme/tokens.dart';
+import '../widgets/guided_setup_dialog.dart';
 import '../widgets/widgets.dart';
 
 class WelcomePage extends StatelessWidget {
@@ -59,6 +60,15 @@ class WelcomePage extends StatelessWidget {
                 crossAxisAlignment: CrossAxisAlignment.start,
                 children: [
                   const _Hero(),
+                  const SizedBox(height: ChainSpace.md),
+                  Align(
+                    alignment: Alignment.centerLeft,
+                    child: OutlinedButton.icon(
+                      onPressed: () => GuidedSetupDialog.show(context),
+                      icon: const Icon(Icons.auto_fix_high),
+                      label: Text(AppLocalizations.of(context)!.guidedSetupTitle),
+                    ),
+                  ),
                   const SizedBox(height: ChainSpace.xxl),
                   // When the hub is down the onboarding checklist
                   // would render dead (all-unchecked, nothing to

lib/widgets/guided_setup_dialog.dart

@@ -0,0 +1,257 @@
+// Guided-setup wizard. Collects scenario / intent / target (plus two
+// adaptive toggles), then calls `chain init --answers` to PREVIEW the
+// assembled plan and `--apply` to write the config. All the policy lives
+// in the Rust deterministic engine (chain_core::guided_setup) — this is
+// a thin UI over the CLI, so the logic never diverges.
+//
+// NOTE: the dropdown option labels are humanised from the canonical
+// kebab-case enum values (trying-out → "Trying Out"); localising those
+// per option is a follow-up. The structural UI + the applied plan
+// (rendered from the CLI's localisable output) are the meaningful parts.
+
+import 'dart:io';
+
+import 'package:flutter/material.dart';
+
+import '../data/error_presentation.dart';
+import '../data/system_actions.dart';
+import '../l10n/app_localizations.dart';
+
+class GuidedSetupDialog extends StatefulWidget {
+  const GuidedSetupDialog({super.key});
+
+  /// Launch the wizard as a modal dialog.
+  static Future<void> show(BuildContext context) => showDialog<void>(
+        context: context,
+        builder: (_) => const GuidedSetupDialog(),
+      );
+
+  @override
+  State<GuidedSetupDialog> createState() => _GuidedSetupDialogState();
+}
+
+class _GuidedSetupDialogState extends State<GuidedSetupDialog> {
+  // Canonical SetupAnswers enum values (serde kebab-case in Rust).
+  static const _scenarios = <String>[
+    'trying-out',
+    'team-hub',
+    'regulated-production',
+    'building-modules',
+  ];
+  static const _intents = <String>[
+    'hello-world',
+    'extract-text',
+    'extract-summarize',
+    'classify-documents',
+    'build-module',
+  ];
+  static const _targets = <String>[
+    'this-laptop',
+    'home-server',
+    'air-gapped-server',
+    'container',
+  ];
+
+  int _step = 0; // 0 = answers, 1 = review/apply
+  String _scenario = 'trying-out';
+  String _intent = 'extract-summarize';
+  String _target = 'this-laptop';
+  bool _requireApproval = false;
+  bool _dataLocal = false;
+  bool _busy = false;
+  String? _preview;
+  String? _applied;
+
+  String _humanize(String kebab) => kebab
+      .split('-')
+      .map((w) => w.isEmpty ? w : '${w[0].toUpperCase()}${w.substring(1)}')
+      .join(' ');
+
+  String _answersYaml() => 'scenario: $_scenario\n'
+      'intent: $_intent\n'
+      'target: $_target\n'
+      'require_approval: $_requireApproval\n'
+      'data_must_stay_local: $_dataLocal\n';
+
+  Future<String> _writeAnswers() async {
+    final f = File('${Directory.systemTemp.path}/chain-setup-answers.yaml');
+    await f.writeAsString(_answersYaml());
+    return f.path;
+  }
+
+  Future<void> _goReview() async {
+    setState(() {
+      _busy = true;
+      _preview = null;
+    });
+    final path = await _writeAnswers();
+    final r = await SystemActions.chainInit(['--answers', path]);
+    if (!mounted) return;
+    setState(() => _busy = false);
+    if (r.ok) {
+      setState(() {
+        _preview = r.stdout.trim();
+        _step = 1;
+      });
+    } else {
+      showFaiProcessError(context, 'chain init --answers', r.stdout, r.stderr);
+    }
+  }
+
+  Future<void> _apply() async {
+    setState(() => _busy = true);
+    final path = await _writeAnswers();
+    final r = await SystemActions.chainInit(
+      ['--answers', path, '--apply', '--force'],
+    );
+    if (!mounted) return;
+    setState(() => _busy = false);
+    if (r.ok) {
+      setState(() => _applied = r.stdout.trim());
+    } else {
+      showFaiProcessError(context, 'chain init --apply', r.stdout, r.stderr);
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final l = AppLocalizations.of(context)!;
+    return AlertDialog(
+      title: Text(l.guidedSetupTitle),
+      content: SizedBox(
+        width: 460,
+        child: SingleChildScrollView(
+          child: _step == 0 ? _answersStep(l) : _reviewStep(l),
+        ),
+      ),
+      actions: _actions(l),
+    );
+  }
+
+  Widget _answersStep(AppLocalizations l) {
+    return Column(
+      mainAxisSize: MainAxisSize.min,
+      crossAxisAlignment: CrossAxisAlignment.start,
+      children: [
+        Text(l.guidedSetupIntro),
+        const SizedBox(height: 16),
+        _dropdown(l.guidedSetupScenario, _scenarios, _scenario,
+            (v) => setState(() => _scenario = v)),
+        const SizedBox(height: 12),
+        _dropdown(l.guidedSetupIntent, _intents, _intent,
+            (v) => setState(() => _intent = v)),
+        const SizedBox(height: 12),
+        _dropdown(l.guidedSetupTarget, _targets, _target,
+            (v) => setState(() => _target = v)),
+        const SizedBox(height: 8),
+        SwitchListTile(
+          contentPadding: EdgeInsets.zero,
+          title: Text(l.guidedSetupApproval),
+          value: _requireApproval,
+          onChanged: (v) => setState(() => _requireApproval = v),
+        ),
+        SwitchListTile(
+          contentPadding: EdgeInsets.zero,
+          title: Text(l.guidedSetupDataLocal),
+          value: _dataLocal,
+          onChanged: (v) => setState(() => _dataLocal = v),
+        ),
+      ],
+    );
+  }
+
+  Widget _dropdown(
+    String label,
+    List<String> items,
+    String value,
+    ValueChanged<String> onChanged,
+  ) {
+    return InputDecorator(
+      decoration: InputDecoration(
+        labelText: label,
+        border: const OutlineInputBorder(),
+        isDense: true,
+      ),
+      child: DropdownButtonHideUnderline(
+        child: DropdownButton<String>(
+          isExpanded: true,
+          value: value,
+          items: [
+            for (final i in items)
+              DropdownMenuItem<String>(value: i, child: Text(_humanize(i))),
+          ],
+          onChanged: (v) {
+            if (v != null) onChanged(v);
+          },
+        ),
+      ),
+    );
+  }
+
+  Widget _reviewStep(AppLocalizations l) {
+    final applied = _applied;
+    return Column(
+      mainAxisSize: MainAxisSize.min,
+      crossAxisAlignment: CrossAxisAlignment.start,
+      children: [
+        Text(applied != null
+            ? l.guidedSetupApplied
+            : l.guidedSetupReviewHeading),
+        const SizedBox(height: 12),
+        Container(
+          width: double.infinity,
+          padding: const EdgeInsets.all(12),
+          decoration: BoxDecoration(
+            color: Theme.of(context).colorScheme.surfaceContainerHighest,
+            borderRadius: BorderRadius.circular(6),
+          ),
+          // SelectableText keeps the plan copyable (project rule:
+          // anything an operator might want to keep is selectable).
+          child: SelectableText(
+            applied ?? _preview ?? '',
+            style: Theme.of(context).textTheme.bodySmall,
+          ),
+        ),
+      ],
+    );
+  }
+
+  List<Widget> _actions(AppLocalizations l) {
+    if (_busy) {
+      return const [
+        Padding(
+          padding: EdgeInsets.all(12),
+          child: SizedBox(
+            width: 18,
+            height: 18,
+            child: CircularProgressIndicator(strokeWidth: 2),
+          ),
+        ),
+      ];
+    }
+    if (_applied != null) {
+      return [
+        FilledButton(
+          onPressed: () => Navigator.of(context).pop(),
+          child: Text(l.guidedSetupClose),
+        ),
+      ];
+    }
+    if (_step == 0) {
+      return [
+        TextButton(
+          onPressed: () => Navigator.of(context).pop(),
+          child: Text(l.guidedSetupCancel),
+        ),
+        FilledButton(onPressed: _goReview, child: Text(l.guidedSetupNext)),
+      ];
+    }
+    return [
+      TextButton(
+        onPressed: () => setState(() => _step = 0),
+        child: Text(l.guidedSetupBack),
+      ),
+      FilledButton(onPressed: _apply, child: Text(l.guidedSetupApply)),
+    ];
+  }
+}