OQ-11 (handler-level auth observability): Option B — handlers store
resolved identity on Connection via set_identity. Two identity scopes:
connection-level (observability, write-once-read-many) and per-request
(ACL, on OperationContext). Per-request takes precedence for ACL;
connection-level is for logging/audit only.
OQ-19 (session-scoped registries): Protocol doesn't need changes.
OperationEnv must remain a trait (not concrete) to enable session-overlay
pattern. Three-tier registry: core (static, External+Internal), session
(dynamic, Internal-only), promotion (curated review). Documented as
implementation guard in operation-registry.md.
All 19 open questions are now resolved. No open one-way or two-way doors
remain. The architecture is ready for review and implementation.