Fix empty typed constructors

[kragol]

Calling PooledArray(Int) or PooledArray(Int, UInt64) fails because the empty constructors still use the removed Array(T, 0) API. Construct an empty Array{T}(undef, 0) instead, preserving the requested element and reference types. The added package tests cover both constructor forms.

The branch includes the current base and uses Actions cache v4. Coverage uploads use the supported Codecov action, with tokenless uploads for public fork pull requests and GitHub OIDC for repository jobs. Upload failures now fail CI instead of silently skipping coverage reporting.

Validation:

• Full package suite with bounds checks and four threads: 327 checks passed on Julia 1.6.7 and Julia 1.12.6.
• Independent reproduction on current main: all 20 combinations of element and reference types raise MethodError.
• The fixed branch passes 160 checks for empty storage, element/reference types, and adding/removing a value across the same combinations.
• All six hosted checks pass on b319fcaad6f2fa50ecfe4f974194eae9f34144e9: Julia 1.0, stable, nightly, Windows x86, and both Codecov coverage checks. The new upload logs confirm successful coverage reporting.
• git diff --check passes.

Fixes #85.

Co-authored by Codex

AI disclosure: This work was prepared with assistance from OpenAI Codex.

[bkamins]

Thank you for reporting. Could you please add tests for the changed methods?

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.03%. Comparing base (25d6928) to head (b319fca).

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #86      +/-   ##
==========================================
+ Coverage   89.55%   90.03%   +0.47%     
==========================================
  Files           1        1              
  Lines         335      331       -4     
==========================================
- Hits          300      298       -2     
+ Misses         35       33       -2     

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[kragol]

Tests added.

[bkamins]

I have added some more tests. Thank you for contributing.

[quinnj]

The approved constructor implementation is retained. I refreshed the current base and repaired the retired cache integration and silent coverage-upload failure. All six checks pass on this exact head, including Julia 1.0, stable, nightly, Windows x86, and both coverage checks; the upload log confirms the report was accepted.

The full local suite passes 327 checks on both Julia 1.6.7 and 1.12.6. An independent check across 20 element/reference-type combinations reproduces the original MethodError on current main and passes 160 checks on the fixed implementation. No further source finding.

AI disclosure: This work was prepared with assistance from OpenAI Codex.