Bump compat for SUNRepresentations to 0.4

[mtfishman]

Widens SUNRepresentations compat from "0.3" to "0.3, 0.4" in both root and test/Project.toml, plus one ext fix needed for the 0.4 API change.

Ext change

SUNRepresentations 0.4 removed the un-parameterized SUNIrrep(...) constructor — it now throws and requires SUNIrrep{N}(...). The extension was using SUNIrrep((λ..., 0)) which worked in 0.3 but breaks in 0.4. Fix: SUNIrrep{N}((λ..., 0)) — compatible with both 0.3 and 0.4.

c.I continues to work in 0.4 via a Base.getproperty backwards-compat shim that returns the weight, so sector_label is unchanged.

Changes

• ext/GradedArraysSUNRepresentationsExt/GradedArraysSUNRepresentationsExt.jl: SUNIrrep((λ..., 0)) → SUNIrrep{N}((λ..., 0))
• Project.toml: SUNRepresentations = "0.3" → "0.3, 0.4"
• test/Project.toml: SUNRepresentations = "0.3" → "0.3, 0.4"
• Project.toml: version 0.8.4 → 0.8.5

Smoke-tested locally: the SU tests (test_sectors.jl, test_fusion_rule.jl) all pass against SUNRepresentations 0.4.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.18%. Comparing base (18c37c5) to head (fcc64fa).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #161   +/-   ##
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  Coverage   87.18%   87.18%           
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  Files          20       20           
  Lines        1264     1264           
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  Hits         1102     1102           
  Misses        162      162           

Flag	Coverage Δ
docs	0.00% <0.00%> (ø)

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