[Code scan] Keep full from_poscar_path when building surface examples

[njzjz]

This issue is from a Codex global scan of the repository.

init_surf loses the directory component of from_poscar_path.

Evidence:

dpgen/dpgen/data/surf.py

Lines 228 to 233 in 7af5246

	from_poscar = jdata.get("from_poscar", False)
	if from_poscar:
	from_poscar_path = jdata["from_poscar_path"]
	poscar_name = os.path.basename(from_poscar_path)
	ss = Structure.from_file(poscar_name)

When from_poscar is true, the code reads from_poscar_path, takes only os.path.basename(from_poscar_path), and then calls Structure.from_file(poscar_name). A valid POSCAR path outside the current working directory fails because the directory part has been discarded.

Expected behavior: pass from_poscar_path itself to Structure.from_file() or resolve it to an absolute path before changing directories.