feat: add executor gateway contracts

docs/architecture/memind-orchestrator-boundary.md

@@ -86,6 +86,21 @@ The framework-neutral contracts are:
 - `orchestrator-event-v1`
 - `workflow-execution-request-v1`
 - `workflow-execution-decision-v1`
+- `executor-job-request-v1`
+- `executor-job-state-v1`
+- `executor-dispatch-decision-v1`
+
+The Phase 3.2 Executor Gateway owns the adapter registry and executor job state
+transition boundary. Requests contain workspace/artifact references,
+authorization and side-effect policy, timeout, cancellation, fallback, and an
+idempotency key. The store interface requires atomic create-if-absent semantics
+so retries return the original job and conflicting payloads fail closed.
+
+Goosed, Aider, and OpenHands currently appear only as disabled
+`contract-only` adapters. The reference in-memory store is non-durable and is
+not a deployment backend. The compile-time dispatch capability remains false,
+so creating a job records `blocked` state without importing an executor SDK,
+launching a process, or touching a workspace.
 
 The implemented internal API is: