GET/PUT /acl/:object_type/:object_id performed no authorization check, so
any authenticated user could read the permission list of, or grant
themselves view/edit on, any file/tag/category/pool. ACLService now
resolves the object's owner and rejects callers who are neither the owner
nor an admin. SetPermissions also wraps its delete+insert replace in a
single transaction so a partial failure can no longer wipe permissions.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Add UserService (GetMe, UpdateMe, admin CRUD with block/unblock),
UserHandler (/users, /users/me), ACLHandler (GET/PUT /acl/:type/:id),
AuditHandler (GET /audit with all filters). Fix UserRepo.Update to
include is_blocked. Wire all remaining routes.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>