feat: add distributed Lance column updates

[FANNG1]

Summary

• add update_columns_df for fragment-parallel updates driven by a prepared Daft DataFrame
• validate unique live row addresses, safely cast update values, and commit one atomic Lance RewriteColumns transaction
• support URI and namespace-addressed tables
• reject stable-row-ID datasets before fragment writes until pylance can provide the metadata needed for correct CDF updates
• honor commit_lock in the final driver-side commit

This complements the SQL-expression update API proposed in #13 / #26. It covers values computed by arbitrary distributed Daft pipelines and writes them back to existing columns by row address.

Closes #57

Semantics

The input DataFrame must contain _rowaddr, fragment_id, and every target column named in columns. Workers reopen the driver-pinned snapshot, validate the rows, rewrite touched fragments, and return fragment metadata. The driver performs one LanceOperation.Update(update_mode="rewrite_columns") commit against the pinned read version, using the caller-provided commit_lock when present.

Invalid, duplicate, deleted, or stale row addresses fail without committing. Empty input is a no-op. Values are cast to the target Arrow schema with safe=True.

Test plan

• Native full suite: 366 passed, 5 skipped, 2 xfailed, 2 xpassed
• Ray update, driver-side commit-lock, and stable-row-ID fail-fast scenarios: 3 passed
• make check-format
• strict mypy checks for changed files
• uv build

Coverage includes partial multi-fragment updates, no-op behavior, validation and safe casting, deleted/stale addresses, stable row IDs, namespace tables, fixed-size lists, scalar-index correctness, physical file preservation, historical versions, and custom commit locks.

Known limitation

Current pylance bindings do not expose updated_fragment_offsets for RewriteColumns. Those offsets are required to advance _row_last_updated_at_version and keep CDF metadata correct, so this API rejects stable-row-ID datasets before DataFrame execution or fragment writes. Support can be enabled once the binding exposes the required offsets.