fix(parse): forward type predicates to inner style

[quinnj]

Summary

• Forward dictlike, arraylike, and nulllike from JSONReadStyle to its inner st.style so user-defined dispatches on a custom JSONStyle are honored during parsing.

Why

In v1.5.1, JSONReadStyle{O,T,S} was changed to wrap the user-provided style to carry null/dicttype/unknown_fields configuration through. But StructUtils.make() dispatches on the wrapping JSONReadStyle, so a user's dictlike(::CustomJSONStyle, ::Type{A}) = true never fired and make fell through to makestruct instead of makedict. This broke the deserialization pattern that worked in v1.5.0, where the user's style was passed through directly.

Forwarding only the type-routing predicates (dictlike/arraylike/nulllike) was chosen deliberately:

• noarg/kwarg/structlike/fieldtags/fielddefaults are set via macros at the ::StructStyle level, which already match through JSONReadStyle.
• Other JSONStyle-level defaults are inherited by any <: JSONStyle user style.
• Forwarding the rest would create dispatch ambiguities with existing (::JSONStyle, ::Type{<:NamedTuple}) and macro-generated (::StructStyle, ::Type{<:T}) methods.

Closes #453

Test plan

• Added regression test reproducing the exact issue example
• Existing test suite passes (Pkg.test())

🤖 Generated with Claude Code

[codecov]

Codecov Report

❌ Patch coverage is 66.66667% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 90.25%. Comparing base (95024e9) to head (86e3baa).
⚠️ Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
src/parse.jl	66.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #454      +/-   ##
==========================================
- Coverage   90.30%   90.25%   -0.06%     
==========================================
  Files           7        7              
  Lines        1392     1395       +3     
==========================================
+ Hits         1257     1259       +2     
- Misses        135      136       +1     

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