dep-bump: quax to >=0.4.3

[nstarman]

Summary

Bumps quax's floor from 0.3.2 to 0.4.3. No code changes needed — quax.quaxify's public signature is unchanged across this range, so this is a pure version-floor bump.

unxt>=2.0 and equinox>=0.13.8 were also considered as part of this sweep, but:

• unxt>=2.0 is not usable yet. coordinax v0.23.3 (latest release, and the ceiling we're holding to for now) was never updated for unxt 2.0's Quantity/BareQuantity rename. Concretely: basic vector construction with range-checking crashes (eqx.error_if inside coordinax's check_polar_range receives a Quantity where it expects a raw JAX array → TypeError: ... is not a valid JAX type), and other codepaths hit AttributeError: type object 'Quantity' has no attribute 'type_parameter'. With unxt>=2.0 installed against coordinax 0.23.3: 154 doctests and 115 tests fail. I checked coordinax's GitHub — no open PR or unreleased work brings it up to unxt 2.0 yet. The existing unxt>=1.11.2,<2 cap (⬆️ dep-bump: cap unxt below 2.0 #800) stays until it does.
• equinox was already at >=0.13.8 on main — nothing to bump.

Verification

• Full test suite: 1080 passed, 0 new failures.
• Doctests: 4964 passed.
• pre-commit run on the changed files: clean.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.73%. Comparing base (cb80a50) to head (e2cfe11).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #807   +/-   ##
=======================================
  Coverage   95.73%   95.73%           
=======================================
  Files         159      159           
  Lines        6089     6089           
=======================================
  Hits         5829     5829           
  Misses        260      260           

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