sourceAge keyed AgainTo's clause-6 refusal on the stream's bus retention
policy, which SEAT_* and other mesh-internal work queues share without
being one of ADR 0436 §6's module streams — so every seat's ask, once
given up on, was refused delivery again. Added a dedicated metadata key
(WorkQueueMetadata), set only by ModuleStream.Stream() when the
catalogue declared retention: work-queue, and read sourceAge from that
instead of the stream's retention policy. New test proves a seat's own
work queue carries neither that metadata nor the restricted one.
ConsumersOf's carried-module path (a module the tool runner carries, no
account of its own — mesh-mail's real shape) was not passing Queues
through, so its work-queue consumer was missing from the composed list
and PruneHeard would have removed what issueProcess made for it. Fixed,
with a test through Users -> ConsumersOf.
Extracted EnsureStream's config building into StreamConfigFor, a pure
function, so the dead-letters test can assert the restricted metadata
EnsureStream would actually send for a work-queue stream instead of
setting the dead letter's header by hand, which passed whether or not
modstreams.go's out.Restricted = true was there at all.
jochen