feat(dac-wizard): add mandatory checkboxes for steps 1 and 4

- Welcome step: checkbox to confirm understanding of system changes
- Backup step: checkbox to confirm backup was created
- Start/Next buttons disabled until checkboxes are checked
- Add translations for checkboxes (EN/ES/FR/DE)

src/lib/components/DACSetupWizard.svelte

@@ -77,7 +77,9 @@
   let completedSteps = $state(new Set<WizardStep>());
   let dacNodeName = $state('');
   let selectedApps = $state(['QBZ']);
+  let welcomeConfirmed = $state(false);
   let precheckDone = $state(false);
+  let backupConfirmed = $state(false);
   let restartDone = $state(false);
   let showRollback = $state(false);
   let selectedDistro = $state('debian');
@@ -119,7 +121,9 @@
       completedSteps = new Set();
       dacNodeName = '';
       selectedApps = ['QBZ'];
+      welcomeConfirmed = false;
       precheckDone = false;
+      backupConfirmed = false;
       restartDone = false;
       showRollback = false;
       dacCapabilities = null;
@@ -286,6 +290,11 @@
           {#if currentStep === 'welcome'}
             <div class="step-content">
               <p class="body-text">{$t('dacWizard.welcome.body')}</p>
+
+              <label class="checkbox-row">
+                <input type="checkbox" bind:checked={welcomeConfirmed} />
+                <span>{$t('dacWizard.welcome.checkbox')}</span>
+              </label>
             </div>
 
           {:else if currentStep === 'precheck'}
@@ -450,6 +459,11 @@
               />
 
               <WarningBanner variant="info" body={$t('dacWizard.backup.hint')} />
+
+              <label class="checkbox-row">
+                <input type="checkbox" bind:checked={backupConfirmed} />
+                <span>{$t('dacWizard.backup.checkbox')}</span>
+              </label>
             </div>
 
           {:else if currentStep === 'pipewire-config'}
@@ -560,7 +574,7 @@
       <!-- Footer -->
       <footer class="wizard-footer">
         {#if currentStep === 'welcome'}
-          <button class="btn btn-primary" onclick={next}>
+          <button class="btn btn-primary" onclick={next} disabled={!welcomeConfirmed}>
             {$t('dacWizard.welcome.start')}
           </button>
         {:else if currentStep === 'verify'}
@@ -584,7 +598,11 @@
           <button
             class="btn btn-primary"
             onclick={next}
-            disabled={(currentStep === 'precheck' && !precheckDone) || (currentStep === 'restart' && !restartDone)}
+            disabled={
+              (currentStep === 'precheck' && !precheckDone) ||
+              (currentStep === 'backup' && !backupConfirmed) ||
+              (currentStep === 'restart' && !restartDone)
+            }
           >
             {$t('dacWizard.buttons.next')}
           </button>

src/lib/i18n/locales/de.json

@@ -967,6 +967,7 @@
       "title": "Geführte DAC-Einrichtung",
       "subtitle": "Schritt-für-Schritt-Anleitung.",
       "body": "Sie werden Befehle kopieren und im Terminal ausführen. QBZ führt Sie durch jeden Schritt und erklärt alles. Vor Änderungen wird eine Sicherung erstellt.",
+      "checkbox": "Ich verstehe, dass diese Anleitung die System-Audiokonfiguration ändert",
       "start": "Starten"
     },
     "precheck": {
@@ -1013,7 +1014,8 @@
     "backup": {
       "title": "Sicherung erstellen",
       "subtitle": "Erforderlich vor jeder Änderung.",
-      "hint": "Sie können diese Sicherung später bei Bedarf wiederherstellen."
+      "hint": "Sie können diese Sicherung später bei Bedarf wiederherstellen.",
+      "checkbox": "Ich habe die Sicherung erstellt"
     },
     "pipewireConfig": {
       "title": "Mehrere Abtastraten erlauben",

src/lib/i18n/locales/en.json

@@ -1026,6 +1026,7 @@
       "title": "Guided DAC Setup",
       "subtitle": "Step-by-step instructions.",
       "body": "You will copy and run commands in a terminal. QBZ will guide you and explain each step. A backup will be created before any changes.",
+      "checkbox": "I understand this guide modifies system audio configuration",
       "start": "Start"
     },
     "precheck": {
@@ -1072,7 +1073,8 @@
     "backup": {
       "title": "Create Backup",
       "subtitle": "Required before any changes.",
-      "hint": "You can restore this backup later if needed."
+      "hint": "You can restore this backup later if needed.",
+      "checkbox": "I created the backup"
     },
     "pipewireConfig": {
       "title": "Allow Multiple Sample Rates",

src/lib/i18n/locales/es.json

@@ -1026,6 +1026,7 @@
       "title": "Configuración Guiada de DAC",
       "subtitle": "Instrucciones paso a paso.",
       "body": "Copiarás y ejecutarás comandos en una terminal. QBZ te guiará y explicará cada paso. Se creará un backup antes de cualquier cambio.",
+      "checkbox": "Entiendo que esta guía modifica la configuración de audio del sistema",
       "start": "Comenzar"
     },
     "precheck": {
@@ -1072,7 +1073,8 @@
     "backup": {
       "title": "Crear Backup",
       "subtitle": "Requerido antes de cualquier cambio.",
-      "hint": "Puedes restaurar este backup después si es necesario."
+      "hint": "Puedes restaurar este backup después si es necesario.",
+      "checkbox": "Creé el backup"
     },
     "pipewireConfig": {
       "title": "Permitir Múltiples Sample Rates",

src/lib/i18n/locales/fr.json

@@ -967,6 +967,7 @@
       "title": "Configuration guidée du DAC",
       "subtitle": "Instructions étape par étape.",
       "body": "Vous allez copier et exécuter des commandes dans un terminal. QBZ vous guidera et expliquera chaque étape. Une sauvegarde sera créée avant toute modification.",
+      "checkbox": "Je comprends que ce guide modifie la configuration audio du système",
       "start": "Commencer"
     },
     "precheck": {
@@ -1013,7 +1014,8 @@
     "backup": {
       "title": "Créer une sauvegarde",
       "subtitle": "Requis avant toute modification.",
-      "hint": "Vous pourrez restaurer cette sauvegarde ultérieurement si nécessaire."
+      "hint": "Vous pourrez restaurer cette sauvegarde ultérieurement si nécessaire.",
+      "checkbox": "J'ai créé la sauvegarde"
     },
     "pipewireConfig": {
       "title": "Autoriser plusieurs taux d'échantillonnage",