Create AuditPageHelper with requirePurgePost() and findOrRedirect()
to eliminate duplicated POST/CSRF guard boilerplate across 4 purge
pages and find-or-redirect boilerplate across 4 view pages. Each page
retains its stream-specific logic (system-audit event recording,
user-lifecycle snapshot/restore).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>