docs(openapi): add Human in the Loop API endpoints (#4079)

* docs(openapi): add Human in the Loop API endpoints

Add HITL pause/resume endpoints to the OpenAPI spec covering
the full workflow pause lifecycle: listing paused executions,
inspecting pause details, and resuming with input.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* docs(openapi): add 403 and 500 responses to HITL endpoints

Address PR review feedback: add missing 403 Forbidden response
to all HITL endpoints (from validateWorkflowAccess), and 500
responses to resume endpoints that have explicit error paths.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* lint

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Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: waleedlatif1