SCIM: users, groups, queries, PATCH, Bulk and cursors at /scim/v2, over x:Account (SCIM-1 to SCIM-57)

Every SCIM operation becomes the x:Account get, query or set JMAP makes,
as the service principal, so permissions, tenant scope and limits,
address uniqueness and account destruction are enforced in one place.
Discovery is anonymous; everything else takes an API key as a bearer
token and nothing else. Domains open to SCIM carry a flag in the domain
cache. Filters take eq and and, answered from the account indexes, with
unindexed attributes checked on at most 200 candidates. Cursors are
stateless, HMAC-sealed under the server key. PATCH applies to the
resource in memory and saves it as a PUT, so it is all or nothing.
Groups get an address from their display name on the principal's
domain; membership is written on each user.

Every write emits one of five new scim.* events (ids 637 to 641), also
added to the packaged schema. The helpers the surviving SCIM suites
import are rebuilt from the spec; scim_tests runs the new acceptance
suite and the surviving tenant isolation suite, and both pass.

resources/schema/schema.json.sha256

@@ -1 +1 @@
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+-DHPbeChvvEHbLbAO3wDU6KCP8HrzaWZHfkka30YoIU