business: the human adds and changes role instances from the CLI and the Console (row 165, Q171, #1662)

`mosaic business instances BUSINESS` reads the role instances, and
`mosaic business instance add|set` writes one add or change through the
broker's new human-only `instances` and `instances.set` verbs. The writer is
packages/business/src/instance-settings.mjs. It takes the caller's revision,
validates the next document, refuses a definition that declares credentials
(organization-credentials-out-of-scope), keeps protected instances as they
are, logs the human as the actor, and says when the running bus needs a
restart. Neither command restarts the bus.

The writer refuses the instance ids human and tester with invalid-request,
because the broker refuses a business whose roles use either name when the
bus starts.

The Console's Settings view shows the instances and, under --send only,
posts to POST /api/instances with the exact Origin and same-origin Fetch
Metadata. A refusal keeps the draft. An answer without the view's shape is
outcome-unknown (503). The page's public/ diff carries the decision 123 go
in mos-0832.

Neither verb is in ORGANIZATION_KEYS, so no agent tool reaches them.