[OTel]: Complete replay and chained-execution conformance coverage

Start with the conformance package at the referenced commit, especially its handlers, template.yaml, src/Makefile, README, local tests, and tests/test_otel_examples.py; read the linked shared PR #131 and workflow contract tests before changing caller inputs. Determine the service guarantee for case 21 event ordering from cloud history and trace evidence, then update the owning fixture or requirement if ordering is variable. Done means focused cases 21–24 and 27 are registered and documented in both views, deferred cases remain explicitly unsupported, and cloud qualification results and revisions are recorded.

Parent: #873 — Remaining Python OpenTelemetry work.

Track the remaining conformance coverage and qualification represented by PR #796, using dc736d5 as the current reference. Implement through focused conformance PRs; keep runtime and testing-library fixes in their existing issues.

Coverage to deliver

Case 11's replay-barrier fix is already delivered by merged #864. Reuse it as a regression control rather than duplicating that implementation. PR #796 currently targets main; its description still contains historical stack text, so use the actual branch state when preparing a smaller PR.

Implementation scope

• The owning package is packages/aws-durable-execution-sdk-python-conformance-tests-otel: handlers, template.yaml, src/Makefile, README, and local public-handler tests.
• Keep requirement-to-handler mappings, deployed function names/targets, and the local catalog assertions synchronized in both Invocation and Execution views.
• Preserve the current shared workflow/catalog defaults to the conformance repository's main, the manual conformance_test_ref override, and SDK handlers built from the exact commit under test. Validate the shared workflow's current inputs/secrets contract when changing the caller.
• The shared orchestrator runs the Invocation and Execution suites. Existing legacy long-running templates/tests are not a request to re-enable that suite.
• Coordinate language-neutral requirements and runner changes in aws/aws-durable-execution-conformance-tests, including the related work in shared PR #131. Use the public SDK API rather than compensating for a missing SDK capability in a handler.

Deferred callback qualification

Keep cases 25–26 explicitly NOT_IMPLEMENTED with issue references until their prerequisites are ready. Their deferred source and tests remain available at 6484e577.

• Case 25: requires terminal status/event semantics (#853) and empty-error history/runtime consistency (#862).
• Case 26: requires replay-completion telemetry (#854), callback updated-operation production (#860), and input acknowledgment (#861). Preserve the assertion inside the observed step that completion has already reached the exporter, plus raw export counts at both later barriers; recorded timestamps alone do not prove delivery order.
• Additional case 17 error regression: requires error snapshot isolation (#852) and the applicable callback-error fixes. The existing case 17 handler remains active.

Before restoring these tests, correct their history expectations: included diagnostic payloads are untruncated, while metadata-only history omits payloads and cannot reconstruct error details. The empty callback-failure Error.Payload service shape remains unverified against deployed AWS Lambda and needs evidence or an explicit qualification decision.

Known qualification gap

PR #796 reports that the S3 Execution-view job failed case 21 because WaitSucceeded preceded InvocationCompleted by 63 ms, contrary to a fixed history-order expectation. The execution returned before-after successfully. Determine which event order the service contract guarantees, collect the relevant trace/history evidence, and fix the owning requirement/fixture if the order is legitimately variable. Preserve the saved-step, result, and telemetry assertions; do not count execution success alone as conformance.

Acceptance criteria

• Cases 21–24 and 27 have public-API handlers, template/Makefile registration, documentation, and focused local regressions in both views.
• Case 11 remains covered by #864's implementation and tests.
• The complete catalog accounts for active and deferred requirements; unsupported cases are never reported as passing.
• Case 21's cloud history-order failure is resolved or explicitly dispositioned with service evidence and the appropriate shared-repository change.
• Restore deferred cases 25–26 and the additional case 17 regression after their implementation prerequisites land, through separate focused PRs as needed.
• Qualify the intended behavior against the deployed Invocation/Execution backend matrix, including raw export counts and parent/trace identity. Link exact SDK/catalog revisions and run results.
• Update the PR/README to reflect current coverage, dependencies, and validation; identify changed test expectations and their reasons.

Starting points and validation

Reference files at the current PR head:

• Handler and test package
• Catalog/mapping regression tests
• Workflow contract tests

Use the repository's pinned Hatch version and run the package tests and focused workflow tests, plus package lint/format and commit-message checks. The PR description reports 75 local package tests on Python 3.13.17 and an earlier 10-test workflow validation; those are historical results, not new validation performed while filing this issue. Cloud qualification remains a separate requirement.

Case 27 companions: JS #1068 and Java #824.