Fix numpy array conversion for LindiH5pyDataset

[bendichter]

Summary

• Override __array__ and _is_empty on LindiH5pyDataset to prevent h5py's inherited methods from calling self.id.get_space(), which fails because id is a string in lindi's implementation
• Adds regression test for numpy array conversion (np.asarray, np.atleast_2d)

Fixes #120

Test plan

• New test test_numpy_array_conversion passes
• All 41 existing tests pass
• Reproduction code from issue get_space error when using pynapple #120 runs successfully

🤖 Generated with Claude Code

[codecov-commenter]

Codecov Report

❌ Patch coverage is 88.88889% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 81.63%. Comparing base (6a196a7) to head (4254c1a).

Files with missing lines	Patch %	Lines
lindi/LindiH5pyFile/LindiH5pyDataset.py	88.88%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #121      +/-   ##
==========================================
+ Coverage   81.39%   81.63%   +0.23%     
==========================================
  Files          30       30              
  Lines        2784     2793       +9     
==========================================
+ Hits         2266     2280      +14     
+ Misses        518      513       -5     

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[rly]

@bendichter Can you also update this to support datasets with a compound dtype?

edit: I believe self[:] will fail in those cases.

[bendichter]

Addressed review feedback - added copy=False check consistent with h5py and simplified dtype handling.