[deploy-plugin DPB-29] Deferred RFC: AWS event semantics, leaf backing graduation, Radius target graduation

[rickylabs]

Part of #892 (RFC #891; corpus .llm/runs/plan-deploy-plugin--seed/ r5).

RFC-first backlog card: SQS/event conformance design (leaf co-owned); leaf backing catalog graduation (kv/queue provider adapter packages); Radius as a descriptor-selected deploy-aspire variant behind machine-verifiable predicates — pinned Aspire CLI ≥ the first release containing the Radius TS API (microsoft/aspire#18759), deno check of a minimal addRadiusEnvironment fixture, app.bicep emission via aspire publish, the Radius step visible in aspire deploy --list-steps, a recipe-derived binding-verdict fixture; per-environment Recipe capabilities unverified until probed. Anti-scope: no implementation from this card.

Acceptance

• gate: the RFC lands with owner-arbitrated forks before any implementation card is filed

Metadata

Dependencies: DPB-27
Delivery shape: RFC-first, leaf/upstream co-owned