Support JSON::Parse without XS

[fglock]

Summary

JSON::Parse 0.62 cannot load on PerlOnJava because the distribution requires
its XS implementation and no Java replacement is registered:

Can't load loadable object for module JSON::Parse: no Java XS implementation available

The distribution includes Parse.xs and supporting C sources. The generated
Perl files alone are insufficient to provide the parser.

Reproduction and control result

CPAN run 20260826-133506-83222 tested HTML::Make::Page 0.04. It depends on
HTML::Make 0.17, which depends on JSON::Parse 0.62. Both PerlOnJava
backends fail when loading JSON::Parse; the downstream files
t/html-make-page.t and t/options.t cannot start their test plans.

As a control, the exact HTML::Make, HTML::Valid, and JSON::Parse
prerequisites were installed into an isolated system-Perl library. The
unmodified HTML::Make::Page 0.04 suite then passed completely: 2 files and
18 tests.

HTML::Valid is also an XS distribution, but JSON::Parse fails first and is
the immediate blocker for this dependency chain.

Ecosystem impact

CPAN metadata reports 36 reverse dependants for JSON::Parse, including 7
recent dependants. Examples include HTML::Make, HTML::Valid,
Google::Ads::GoogleAds::Client, JSON::Create, and Config::Abstraction.

Proposed investigation

First determine whether a compatible pure-Perl implementation can cover the
public JSON::Parse API and error behavior needed by common callers. If that
is not viable, implement the required parser/tokenizer functionality in Java
and expose it through the module's expected Perl API.

Acceptance criteria

• use JSON::Parse works without a native library on both PerlOnJava backends.
• Add project-owned regression coverage for the implemented public behavior.
• HTML::Make::Page 0.04 passes t/html-make-page.t and t/options.t on
  both backends with its normal CPAN dependency overlay.