feat: audit log viewer in admin dashboard

[lakhansamani]

Problem

Audit logs are now captured via the _audit_logs GraphQL API but there is no UI to view them. Admins need a dashboard page to browse, filter, and search audit events.

Proposed Solution

Add an Audit Logs page to the admin dashboard (web/dashboard/) that:

• Lists audit log entries in a paginated table with columns: timestamp, action, actor (type + email), resource (type + ID), IP address
• Supports filtering by:
  • Action (dropdown with known event types from constants)
  • Actor type (user / admin)
  • Resource type (user / session / webhook / email_template / token)
  • Date range (from/to timestamp picker)
• Supports search by actor email or resource ID
• Shows detail view on row click (full metadata, user agent, etc.)
• Auto-refreshes or has a refresh button

Implementation Notes

• Affected packages: web/dashboard/ (React + Chakra UI + Vite)
• GraphQL query: _audit_logs with ListAuditLogRequest params (already available)
• No backend changes needed — the API is complete
• Security: Only accessible to admin (already enforced by _audit_logs resolver)

Design Considerations

• Consider using a virtualized table for large audit log sets
• Timestamp display should respect the admin's timezone
• Action names could be human-readable labels (e.g., user.login_success → "User Login Success")
• Export to CSV could be a nice-to-have