pipeio_config_patch — snakebids-aware config.yml read/write

Goal

(promoted from note)

Context

(see source note)

Prompt

Implement pipeio_config_patch — snakebids-aware config.yml read/write with YAML anchor resolution, bids() signature mapping, pybids_inputs validation, and diff preview.

Reference capture: 20260325-211127-5b8280.

Acceptance Criteria

• [ ]

Result

(pending)