[Feature]: pluggable SpaceLayout to avoid in-place rename for better performance on PCFS

[mag1c-h]

Purpose

In the default design, a Block file has two states:

• activated – while data is being written
• archived – after the write is finished

The state is encoded in the file name and switched by an in-directory rename.
On some storage systems (e.g. PCFS) this rename is expensive.
This PR introduces an optional layout that keeps the two states in separate directories so the switch becomes a fast cross-directory move.

Modifications

• Turn SpaceLayout into an interface
• Keep the existing behaviour in SpaceShardLayout (state encoded in file name, activated & archived live in the same directory)
• Add SpaceShardTempLayout; when tempDumpDirEnable=true activated files are written to a temporary directory and moved to the final directory on completion

Test

• CI passed with new added/existing test.
• E2E tests in NFSStore passed.