feat(p10): archivage automatique des sessions terminées (rétention configurable)

- DB: migration #10 (sessions.archived_at + index), helpers archive/unarchive/archiveExpired (soft-archive, jamais de DELETE)
- core/retention-settings.ts: session_retention_days (défaut 30, 0=jamais, 1-3650) + session_purge_days (off)
- core/session-archive.ts: scheduler start/stop/sweep (calqué DiscoveryService), câblé dans runDaemon
- pty-manager.list({includeArchived}) + SessionSummary.archived + emitHistoricalUpdate
- routes: GET /sessions?includeArchived, POST/DELETE /sessions/:id/archive, POST /sessions/archive-now
- protocole additif: message WS session_archived (relayé par la gateway, abonnés 'sessions')
- settings: retentionDays/purgeDays exposés et validés dans PATCH /settings
- web: store sessions (showArchived + archive/unarchive), SessionsListView (toggle/badge/actions), SettingsView (slider rétention), i18n EN+FR
- tests: retention-settings + session-archive (vitest) + settings-routes étendu ; acceptance-p10.mjs (sweep, event WS, resume d'une session archivée → 201, rétention=0)

packages/web/src/views/SettingsView.vue

@@ -175,6 +175,26 @@
       </div>
     </section>
 
+    <!-- Sessions (rétention / archivage auto) -->
+    <section class="card flex flex-col gap-3">
+      <h2 class="flex items-center gap-2 text-sm font-semibold text-zinc-100">
+        <Archive :size="16" /> {{ t('settings.sessions') }}
+      </h2>
+      <p class="text-xs text-zinc-500">{{ t('settings.sessionsHint') }}</p>
+
+      <label class="flex flex-col gap-1">
+        <span class="text-xs text-zinc-400">{{ t('settings.retentionDays') }}</span>
+        <input v-model.number="retentionDraft" type="number" min="0" max="3650" class="input w-32" />
+        <span class="text-xs text-zinc-500">{{ t('settings.retentionDaysHint') }}</span>
+      </label>
+
+      <div>
+        <BaseButton variant="primary" :loading="settings.saving" :disabled="!retentionDirty" @click="saveRetention">
+          {{ t('settings.save') }}
+        </BaseButton>
+      </div>
+    </section>
+
     <!-- Sécurité & conformité -->
     <section class="card flex flex-col gap-3">
       <h2 class="flex items-center gap-2 text-sm font-semibold text-zinc-100">
@@ -240,7 +260,7 @@
 <script setup lang="ts">
 import { computed, onMounted, ref } from 'vue';
 import { useI18n } from 'vue-i18n';
-import { AlertCircle, Bell, BellOff, Check, CheckCircle2, Coffee, Copy, Download, FolderOpen, KeyRound, Plus, RefreshCw, ScanSearch, Send, Server, Shield, SlidersHorizontal, Terminal, Trash2, X } from '@lucide/vue';
+import { AlertCircle, Archive, Bell, BellOff, Check, CheckCircle2, Coffee, Copy, Download, FolderOpen, KeyRound, Plus, RefreshCw, ScanSearch, Send, Server, Shield, SlidersHorizontal, Terminal, Trash2, X } from '@lucide/vue';
 import type {
   AuditLogEntry,
   AuditLogsResponse,
@@ -387,6 +407,22 @@ async function saveClaude(): Promise<void> {
   }
 }
 
+// ---- Sessions (rétention / archivage auto) ----
+const retentionDraft = ref(0);
+const retentionDirty = computed(() => retentionDraft.value !== settings.retentionDays);
+function syncRetentionDraft(): void {
+  retentionDraft.value = settings.retentionDays;
+}
+async function saveRetention(): Promise<void> {
+  try {
+    await settings.save({ retentionDays: retentionDraft.value });
+    syncRetentionDraft();
+    toasts.success(t('settings.saved'));
+  } catch (e) {
+    toasts.error(e);
+  }
+}
+
 // ---- Sécurité & conformité (audit / RGPD) ----
 const audit = ref<AuditLogEntry[]>([]);
 const auditing = ref(false);
@@ -438,6 +474,7 @@ onMounted(async () => {
   await Promise.all([loadTokens(), settings.loaded ? Promise.resolve() : settings.fetch()]);
   syncDiscoveryDraft();
   syncClaudeDraft();
+  syncRetentionDraft();
   void push.refresh();
 });
 </script>