Add role-based access control with hierarchy: super_admin > team_admin >
engineer > viewer. Adds is_super_admin boolean to User model (migration 010),
centralized backend permissions module, frontend usePermissions hook, and
UI enforcement (conditional Create/Edit buttons, editor redirect for viewers,
role badge in header). All endpoint admin checks updated from role=="admin"
to is_super_admin.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Fix broken JWT token refresh that caused "Failed to load trees" after
idle timeout. The refresh endpoint expected token as query param but
frontend sent it as Authorization header. Added proper dependency
(get_refresh_token_payload) and refresh queue to handle concurrent 401s.
Also fix seed trees not being visible to non-admin users by updating
the seed script to set is_public/is_default on existing trees.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>