Fix unsafe logger access patterns in workflow files — a Devin (Cognition) bot flight

From the pull request description

# Fix unsafe logger access patterns in workflow files ## Summary Fixed unsafe logger access patterns across multiple Vellum workflow files that were causing failures when `WorkflowContext` doesn't have a `logger` attribute defined. Replaced direct `getattr(self._context, "logger")` calls with safe…

Excerpt (first 300 characters) — the full description is on GitHub.