[stable/10] Backport #96: sync client throws ApiException on HTTP 4xx/5xx for no-content operations (#94) #97

Backport of #96 (fixes #94) to stable/10, so it ships in a 10.0.x release.

Problem (#94): CamundaClient builds Guzzle with http_errors => false, and the generated *WithHttpInfo methods for no-content operations (completeJob, failJob, throwJobError, updateJob, completeUserTask, ...) never check the status. A 4xx/5xx is returned as success (null). This hides failed job completions; the SDK performance matrix (camunda/sdk-performance-matrix) hit it with a 415 on completeJob.

What to backport from #96 (merge commit 409c288):

• hooks/post_gen/0326_sync_no_content_http_errors.php (post-gen hook)
• tests/Acceptance/SyncNoContentHttpErrorHandlingTest.php
• Regenerate generated/ on stable/10 from its own (stable/8.10) spec, rather than cherry-picking main's generated files (main tracks a newer spec).

Done when: PR into stable/10 with the hook and test, regenerated code, CI green. A 10.0.x release follows once the stable/10 publish workflow can import its Vault secrets: the run on 2026-11-12 failed at 'Import secrets' (url not supplied; the repo has no VAULT_* secrets).