feat: retain provider response observations in native history - #5512

Approved at 71ae120 after coordinator and two independent static reviews, including the saved-state security boundary.

Terminal observations preserve supplied status/reason/counters before existing completion/error handling, with native occurrence IDs distinct from provider IDs. Unknown counters remain unknown; normalized legacy accounting is labeled separately. Restore, fork, rollback and compaction retain reporting identities without making observations model input or execution authority. Failed required observation append propagates Fatal through sampling and local/remote compaction without issuing a replacement provider request; cancellation and ephemeral behavior remain explicit. Reviewed the regression coverage and patch manifest checksum. No actionable findings.

Hosted native CI is still in progress; change selection, lint and docs have passed. No candidate code or local tests executed. Retained observations do not establish complete billing history; older readers may reject new snapshot records as documented.

New hosted evidence exposes a deterministic failure in the response-history test introduced here, inherited by #5508. Requesting the focused test-contract correction below; this does not establish a new runtime status regression. Coordinator and independent static investigation; no candidate code or local tests executed.

The regression now accepts both existing SDK settlement outcomes (failed or cancelled) while still requiring NativeError, provider-completed history, received usage, and exactly one request. This resolves the previous assertion finding; the separate hosted timeout remains a CI follow-up. Coordinator and independent static review complete. Current-head hosted checks: {'SKIPPED': 4, 'SUCCESS': 3, 'IN_PROGRESS': 2}. Native/SDK checks remain pending. No candidate code or local tests executed.

New hosted evidence reveals missing provider response history in the rejection path. Requesting changes on this distinct finding; the prior status-assertion correction remains valid. Coordinator and independent static review; no candidate code or local tests executed.

The observation acknowledgment resolves my earlier rejection-path history finding: the stream mapper cannot process the terminal interceptor rejection until Core has persisted the preceding provider observation. The acknowledgment is one-shot across pending polls, and consumer drop releases a waiting producer. Persistence failure cancels and joins this sample's tools without cancelling the owning turn or replacing the fatal retention error. Source review also verified retained receipts, response facts and late execution rows coexist after base integration. Coordinator and independent static re-review found no new actionable issue. Hosted native/SDK CI remains pending; no candidate code or local tests executed.

Approved after coordinator and independent static re-review of the base integration. Direct tree comparison shows 97 of 102 changed files equal the current base. The remaining overlap preserves the existing response-history projection and test registration; the native observation patch changes only rebased context/whitespace, retaining the previously reviewed receipt-ordering fix.

Hosted CI remains pending. Static review only; no candidate code or local tests ran.

Approved after static re-review. Saved-login and previously reviewed passive-request metadata integration preserves response-observation routing and the existing feature patch. Hosted CI/native builds remain pending. No candidate code or tests executed.