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)
Johan LEROY
c8dd539571