Fix shared create response ordering without overwriting subscribe models

[chen21019]

Root cause

Native QA captured subscribe updating a created Volume to inactive before its
initial HTTP 201 response arrived. The old create snapshot then overwrote the
canonical Store model with registering fields. Backend creation succeeded;
frontend lifecycle acceptance did not. Existing failed receipts remain HOLD.

Scope

• Use an existing exact-ID/concrete-type canonical model only for ID-less save
  POST/201 in the same Store, generation and API base.
• Do not import stale nested create fields over that model; preserve draft-save
  identity, subtype/base aliases and HTTP metadata.
• Clear reused create markers from existing saves and action dispatch.
• Keep GET, PUT, actions, uncached/non-201, 204 and errors on their normal paths.
• New api-store compatibility v5 archive, unchanged dependency graph, numeric
  Web171 version and aligned lock/baseline/gates/documentation. No auth or API
  authorization, backend, production, HAProxy or OIDC changes.

Evidence and remaining gate

Installed-package Chrome validation: 36/36 PASS, 0 failure/skip/todo; ten new
cases include 100 deterministic deferred-barrier iterations without sleeps.
Independent source review found no blocker; its action-options gap was closed.
Official exact-source validation is running at
https://github.com/PastureStack/web-console/actions/runs/37092519936 .
Immutable release, Server packaging and native fresh-volume QA are subsequent
gates, not complete permission/resource/locale-matrix PASS.