GROOVY-12144: Fix AstNodeToScriptAdapter decompiler rendering fidelity (GROOVY_4_0_X backport)

[leonard84]

This backports the eight decompiler-fidelity fixes from master (#2682, commit 4b27025962) to GROOVY_4_0_X. AstNodeToScriptVisitor rendered several constructs so they did not round-trip; each fix is localized to one visitor method:

1. Nested generic type arguments dropped (Map<String, List<Integer>> → Map<String, List>) — visitGenerics recurses into concrete args.
2. Range bound exclusions dropped — visitRangeExpression.
3. Elvis rendered as a duplicated ternary (c ?: d → c ? c : d, evaluating c twice) — visitShortTernaryExpression emits ?:.
4. Attribute access lost the at-sign (obj.@f → obj.f) — visitPropertyExpression emits .@ for an AttributeExpression.
5. Explicit zero-arg closures lost the arrow ({ -> ... } → { ... }) — visitClosureExpression distinguishes a null parameter list from Parameter.EMPTY_ARRAY.
6. Safe index access lost safe navigation (list?[0] → list[0]) — visitBinaryExpression.
7. Numeric literal type suffixes dropped (42L/2.5f/3.5d/10G) — visitConstantExpression re-appends L/F/D/G.
8. Explicit method-call type arguments dropped (Collections.<String>emptyList()) — visitMethodCallExpression.

One regression test per defect (GroovyTestCase style, matching the existing test class). Existing tests reconciled to the corrected output: testTernaryOperaters (elvis), testGenericsInMethods (nested generics now preserved), testLogAnnotation (@Log's Level.FINE is an AttributeExpression, now renders Level.@FINE).

Branch adaptation (fix 6): on 4.0 the safe-index operator carries its own ?[ operation text (the file has drifted from master), so visitBinaryExpression'"'"'s subscript detection was widened to recognise ?[ and emit ?[/[ per isSafe(). Verified to round-trip.

Tests: AstNodeToScriptAdapterTest 71/71 (forced recompile+run). Whole-module has 3 pre-existing SwingBuilderConsoleTest GUI failures unrelated to this change (confirmed against the untouched baseline).

Master PR: #2682

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🤖 Prepared with Claude Code (Opus 4.8) on behalf of @leonard84.

[daniellansun]

Merged. Thanks.