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/server/test/retention-settings.test.ts

@@ -0,0 +1,63 @@
+// Réglages de rétention des sessions (P10) : validateurs + lecture/écriture DB.
+import { afterEach, beforeEach, describe, expect, it } from 'vitest';
+import { openDb, setSetting, type Db } from '../src/db/index.js';
+import {
+  DEFAULT_PURGE_DAYS,
+  DEFAULT_RETENTION_DAYS,
+  PURGE_DAYS_KEY,
+  RETENTION_DAYS_KEY,
+  normalizePurgeDays,
+  normalizeRetentionDays,
+  readPurgeDays,
+  readRetentionDays,
+} from '../src/core/retention-settings.js';
+
+let db: Db;
+beforeEach(() => {
+  db = openDb(':memory:');
+});
+afterEach(() => db.close());
+
+describe('normalizeRetentionDays', () => {
+  it('accepte 0 (= jamais)', () => {
+    expect(normalizeRetentionDays(0)).toBe(0);
+  });
+  it('accepte une valeur dans les bornes', () => {
+    expect(normalizeRetentionDays(30)).toBe(30);
+    expect(normalizeRetentionDays(1)).toBe(1);
+    expect(normalizeRetentionDays(3650)).toBe(3650);
+  });
+  it('rejette hors bornes, non-entier, non-nombre', () => {
+    expect(normalizeRetentionDays(-1)).toBeNull();
+    expect(normalizeRetentionDays(3651)).toBeNull();
+    expect(normalizeRetentionDays(1.5)).toBeNull();
+    expect(normalizeRetentionDays('30')).toBeNull();
+    expect(normalizeRetentionDays(null)).toBeNull();
+  });
+  it('purge partage exactement les mêmes règles', () => {
+    expect(normalizePurgeDays).toBe(normalizeRetentionDays);
+  });
+});
+
+describe('readRetentionDays / readPurgeDays', () => {
+  it('défaut quand absent', () => {
+    expect(readRetentionDays(db)).toBe(DEFAULT_RETENTION_DAYS);
+    expect(readPurgeDays(db)).toBe(DEFAULT_PURGE_DAYS);
+  });
+  it('lit une valeur posée', () => {
+    setSetting(db, RETENTION_DAYS_KEY, '7');
+    setSetting(db, PURGE_DAYS_KEY, '90');
+    expect(readRetentionDays(db)).toBe(7);
+    expect(readPurgeDays(db)).toBe(90);
+  });
+  it('0 est une valeur valide (désactivé)', () => {
+    setSetting(db, RETENTION_DAYS_KEY, '0');
+    expect(readRetentionDays(db)).toBe(0);
+  });
+  it('tolère une valeur corrompue → défaut', () => {
+    setSetting(db, RETENTION_DAYS_KEY, 'not-a-number');
+    expect(readRetentionDays(db)).toBe(DEFAULT_RETENTION_DAYS);
+    setSetting(db, RETENTION_DAYS_KEY, '99999');
+    expect(readRetentionDays(db)).toBe(DEFAULT_RETENTION_DAYS);
+  });
+});