refactor: unify sync consent into PlayerSyncPreferencesStore
PlayerSyncPreferencesStore is now the single source of truth for all
sync consent (stats, sessions, achievements, server status). The old
syncStats/syncSessions fields on PlayerIdentityStore are legacy-only
and migrated on startup.
- Wire all 4 sync services to check syncPreferencesStore instead of
identityStore.getSyncConsent()
- Expand /atproto sync commands to 4 categories
- Client-side /atproto sync now updates PreferencesManager and sends
SyncPreferencesPacket to server
- Add consent toggles to AtProtoConfigScreen
- Remove old logSyncConsentChange from SecurityAuditor
- Add migration: extractLegacySyncConsent + migrateFromIdentityStore