BED-8746: migrate to app.defer, update OH version dependency

[StranDutton]

Replaces @dlt.defer with @app.defer in organization.py for the _workflow_file_contents function.

@dlt.defer functions execute lazily outside the generator iteration loop, so exceptions in them bypass the safe resource wrapper and crash the entire pipeline. @app.defer wraps them with error handling that logs the exception allows the pipeline to continue.

Changes:

• organization.py: @dlt.defer → @app.defer
• pyproject.toml: added openhound>=0.2.7 to runtime dependencies
• uv.lock updated accordingly

Verified locally by starting a collection ✅

Depends on OpenHound PR #37