fix: parse dense Mo::Inline double-colon barewords

[fglock]

Summary

Fixes #1217.

TestML::Base 0.54 uses dense Mo::Inline-generated code containing :: as a
bareword between concatenation operators inside a braced hash dereference.
The parser treated this as an invalid leading package-qualified name and
reported a missing closing brace. Parse :: as the bareword string in this
context.

Validation

• System Perl regression test
• JVM backend regression test
• Interpreter backend regression test
• TestML::Base 0.54 module load on both backends
• Full make gate after rebase: passed

[fglock]

UAT follow-up

The synced Perl core tests reproduce the reported results:

• op/equ.t: fails in the same way on this branch and clean origin/master.
  The failure is the pre-existing unsupported equ/neu and ===/!==
  operator semantics, not the TestML::Base fails to compile due to dense Mo::Inline syntax #1217 parser change.
• op/tie_fetch_count.t: passes all 347 tests on this branch and clean
  origin/master.

The synchronized bundled Perl library updates have also been added in commit
a8b5f6ff7.

[fglock]

Follow-up validation and fix for the synced UAT regressions:

• Implemented Perl 5.44 defined comparison operators equ, neu, ===, and !== across parsing, JVM emission, bytecode interpretation, comparison chaining, and overload dispatch.
• Added focused regression coverage in src/test/resources/unit/defined_comparison_operators.t.
• Full make passes.
• Synced UAT op/equ.t: 87/87 on both JVM and interpreter backends.
• Synced UAT op/tie_fetch_count.t: 347/347 on both JVM and interpreter backends.

The changes are in commit f69f48657.

[fglock]

Additional fix for the remaining interpreter parity gap:

• The bytecode compiler now executes nested comparison ASTs as true Perl chains: left-to-right, each operand once, with short-circuiting after the first false comparison.
• The permanent regression test now covers equ chains, mixed ===/== chains, and side-effect-based short-circuit behavior.
• Full make passes; the focused regression passes on both JVM and --interpreter.

Latest commit: 098b8eb79.

[fglock]

Fixed the latest UAT regression in commit 707b43459.

The new defined-comparison operators were checking tied operands for definedness and then comparing the original tied wrapper, causing a second FETCH. They now FETCH once and compare the fetched value.

Validation:

• op/tie_fetch_count.t: the four reported cases (===, !==, equ, neu) now pass on JVM and --interpreter.
• Full make: passed.
• The remaining 128 failures are unchanged pre-existing baseline failures; the UAT delta is resolved.