feat: support read deletion vector to arrow

[luoyuxia]

Purpose

Linked issue: close #140

Support reading deletion-vector tables through the Arrow read path.

Brief change log

• add split-level deletion vector loading and row filtering in ArrowReader
• reject reading primary-key tables without deletion-vectors.enabled
• fix manifest add/delete merging to use full file identity via ManifestEntry::identifier()
• introduce lightweight CoreOptions accessors for deletion-vector and split-size options
• update integration/dev helpers and table read tests to cover DV table reads

Tests

API and Format

No storage format change. The read path now supports deletion-vector filtering for Arrow reads and returns an explicit unsupported error for primary-key tables without deletion vectors.

Documentation

No documentation update.