feat(esopull): runtime body sync for EsoPull streaming mode

- New esopull_sync.cu: DecodeCellsToPhysical + EncodePhysicalToCells
  (compact-list mode, ddf_shifting-aware, encode applies collision).
- sync_bodies() now branches for double_buffer vs esopull: decode
  backing layout to physical DDF on GPU -> host patch -> collide +
  encode back to backing layout. No temp_gpu, no full-grid copy.
- 4 new integration tests covering esopull add/remove/cycle/roundtrip.
- ddf_shifting + esopull + sync_bodies jointly verified (1300 steps
  stable after add/remove).
- Bump version to 0.5.0.

Co-authored-by: Cursor <cursoragent@cursor.com>

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "CelerisLab"
-version = "0.4.0"
+version = "0.5.0"
 description = "GPU-accelerated Lattice Boltzmann Method (LBM) CFD solver using CUDA"
 readme = "README.md"
 requires-python = ">=3.8"