fix(indexing): audit factual contracts and close validation gaps

[d-v-b]

AI-authored PR based on the results of fact-checking factual statements in docstrings and documentation in zarr-indexing. A lot of alleged falsehoods and inaccuracies were found. I haven't confirmed all of these, but I am reasonably confident that this change makes these descriptions more accurate.

🤖 AI text below 🤖

Correct factual claims in zarr-indexing's documentation, source comments, examples, and testing contracts, and fix the correctness defects exposed while checking those claims.

Runtime changes:

• Reject mixed boolean/integer wire arrays and coordinates outside intp before NumPy can coerce or wrap them.
• Reject computed canonical bounds outside signed 64-bit range and enforce the existing input-rank limit consistently across message forms, preserving normalization idempotence.
• Route intersections with shared affine/index-array dependencies to the explicit unsupported path instead of returning extra coordinates. Planning this mixed case now raises NotImplementedError, consistent with its general classification.
• Group signed chunk-coordinate tuples without collisions; distinct chunks such as (-1, 0) and (0, -1) must remain separate.

Expand regression coverage across integer widths, indexing modes, origins, normalization boundaries, map order, negative chunk IDs, repeated points, and one-/two-axis dependencies. Keep main's existing unsigned-selector fix.

The documentation now distinguishes structural box classification from density/order, actual NumPy compatibility from tested examples, metadata inspection from tokenization reads, and parent partition context from direct part resolution. It also corrects TensorStore wire/partition comparisons, cache and benchmark claims, and source integration descriptions. Finite index_array_bounds remain unenforced during engine loading and are explicitly documented as a limitation.

Validation against ba883a556 (also the upstream main revision at submission):

• Full package tests and doctests: 1,521 passed, no skips, including TensorStore 0.1.84 and Dask 2026.8.0.
• Strict documentation build passed.
• Applicable changed-file repository checks passed, including Ruff, mypy, codespell, and numpydoc.
• Package Pyright check: 0 errors, 90 warnings with the Hatch interpreter explicitly selected.

Corresponding fork review: d-v-b#333.

[read-the-docs-community]

Documentation build overview

📚 zarr-indexing | 🛠️ Build #34545768 | 📁 Comparing 89bee02 against latest (ba883a5)

  🔍 Preview build  

24 files changed · ± 24 modified

± Modified

• index.html
• api/index.html
• design-notes/index.html
• guide/index.html
• ndsel/index.html
• api/boundary/index.html
• api/chunk_resolution/index.html
• api/domain/index.html
• api/errors/index.html
• api/grid/index.html
• and 14 more...

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.34%. Comparing base (5d60db6) to head (89bee02).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4345   +/-   ##
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  Coverage   94.34%   94.34%           
=======================================
  Files          92       92           
  Lines       12935    12935           
=======================================
  Hits        12203    12203           
  Misses        732      732           

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