- Create util/validation.py with UUID validation helpers
- Create tools/helpers.py with shared utilities (get_inputs_from_schema, etc.)
- Add shared credential matching utilities to utils.py
- Refactor run_block to use shared matching with discriminator support
- Extract _create_stream_generator in routes.py
- Update run_agent.py to use shared helpers
Preserves discriminator logic for multi-provider credential matching.