Fix JSON coordinate units

[MoseyQAQ]

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Linked Issue

Fix #7750

Unit Tests and/or Case Tests for my changes

• Commands run:
• Result summary:
• Checks not run, with reason:

What's changed?

• The unit of coordinate has been changed from bohr to Angstrom, in order to match the related document. The corresponding unit test has also been updated.

Governance Notes

• INPUT/docs changes:
• Core module impact:
• Exceptions requested:

[Stardust0831]

This PR changes JSON coordinates from tau * lat0 (Bohr) to tau * lat0_angstrom, matching the documented Angstrom unit. It seems cell may have the same issue: both init and output write raw latvec, while the documentation says cell is in Angstrom. Should it also be multiplied by lat0_angstrom?

[MoseyQAQ]

@Stardust0831 I agree with you. I didn't find this issue since I always use:

LATTICE_CONSTANT
1.8897261258369282

But for some old examples, LATTICE_CONSTANT was set to other values. I have corrected the unit of cell.

[mohanchen]

LGTM. Thanks for your contribution!