Local fixture source

from pipewhy.adapters.local import LocalFixtureAdapter

source = LocalFixtureAdapter("tests/fixtures/local")
discovery = source.discover(batch_size=2)
baseline = source.read(2, "baseline-v1", batch_size=1)
changed = source.read(2, "mutation-v1")
unavailable = source.read(3, "missing-v1")
lineage = source.lineage()

The repository example fixtures are supplied externally; they are not bundled into the wheel. The adapter captures and validates the source at construction. It returns owned C1 column arrays, full normalization profile identities, explicit read counts/status/reasons and declared lineage evidence. A failed read has no successful batches and stays distinct from a complete empty dataset. Only integer and Decimal fixture inputs are currently supported. This fixture source provides no live filesystem watching or enterprise source consistency guarantee.

See blueprint/LOCAL_ADAPTER_CONTRACT.txt for fixture identity and protocol details.