AI settings are no longer written for a phantom account

When a plugin package is installed — and again on every portal start, as part of the routine repair pass — the platform registers the package's agents and skills in each user's AI settings, so new content shows up in everyone's pickers right away.

The list of "each user" accidentally included one entry that is not a user at all: the built-in definition of the User node type itself. Treated as an account, it produced a write into a storage area named after it that no portal provisions, which failed every single time — once per installed package, on every pod, on every start. The failures were caught and retried on the next start, so nothing a real person entered was ever touched or lost, but the logs filled with recurring database errors and an incident was filed for what looked like missing storage.

The phantom entry is now filtered out where the user list is built, and a regression test pins it there: real accounts keep receiving every package's sources, and the type definition is never mistaken for an account again.