Write Range and Delta offsets in Lance 2.3

[Xuanwo]

Goal

Use Range and Delta block compression for Lance 2.3 variable-width mini-block offsets when it reduces complete chunk size.

Scope

• Compare legacy interleaved-flat and generic offset containers.
• Keep the legacy candidate when generic metadata or payload placement is not beneficial.
• Preserve Lance 2.0-2.2 bytes, SparseLayout wire, and chunk-local random-read behavior.
• Add representative encode, scan, range, take, and multi-chunk tests and benchmarks.

Context

This is PR 5 of the Generic Block Compression stack extracted from #8002. It depends on the generic offset reader.