RBAC editor was failing with 403 Forbidden when trying to edit permissions
for users who have access via the old dossier_access table but not the new
access grants table.
Added fallback logic to CanManageDossier and CanAccessDossier:
1. Check new RBAC system (access table) first
2. If no grant found, check old dossier_access table
3. For manage: check can_edit = 1
4. For access: check status = 1
This allows existing access relationships to work with the new RBAC editor
while we migrate data from old to new system.
Fixes: "Forbidden" error when editing permissions for legacy access grants
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>