Extend the existing Branded<B> machinery (CallId/SessionId/AgentId) to the
unbranded cross-boundary IDs that meet the brand.ts policy bar — chiefly the
model-facing bash task id (BashTask.id, the `bash-N` counter that shares
SessionId's `name-N` shape) and a distinct OwnerToken brand for the bash
owner token — and fix the brand erosion where existing brands decay back to
`string` at Map keys and method params.
Scoped focused per the "not every string needs a brand" policy: ModelId,
ToolName, numeric ordinals, and validated construction are listed as
deferred extensions, not in-scope work. Filed under proposed/architecture.