Pass mini-block compression context explicitly

[Xuanwo]

Goal

Pass compression context explicitly through the mini-block compression path without changing persisted format or codec selection.

Scope

• Add the explicit compression context to MiniBlockCompressor::compress.
• Migrate existing compressors and callers mechanically.
• Preserve all current writer output and reader behavior.

Context

This is PR 1 of the Generic Block Compression stack extracted from #8002.