Fix -NaN emission for enum members in declaration output

[Copilot]

NaN comparisons always return false in IEEE 754, so value >= 0 falls into the negative branch, emitting -NaN instead of NaN. Same issue with Infinity.

export declare enum E {
    A = -NaN  // tsgo emits -NaN, should be NaN
}

• Added IsNaN() and IsInf() checks before the sign check in transformEnumDeclaration and CreateLiteralConstValue, matching the existing pattern already used in constantExpression and the const enum inliner
• Added test case covering NaN, -NaN, Infinity, -Infinity enum member values

[Copilot]

Pull request overview

Fixes incorrect -NaN emission in declaration output for enum members. Since NaN >= 0 is false in IEEE 754, NaN values fell into the negative branch and were emitted as -NaN. The fix adds explicit IsInf()/IsNaN() checks before the sign-based branch in the two emit paths.

Changes:

• Handle NaN/±Infinity explicitly in transformEnumDeclaration before the value >= 0 sign check.
• Apply the same handling in EmitResolver.CreateLiteralConstValue.
• Add a compiler test case with baselines covering NaN, -NaN, Infinity, and -Infinity.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
internal/transformers/declarations/transform.go	Guard NaN/Infinity before sign check in enum declaration transform
internal/checker/emitresolver.go	Guard NaN/Infinity in CreateLiteralConstValue
testdata/tests/cases/compiler/declarationEmitEnumNaN.ts	New test case
testdata/baselines/reference/compiler/declarationEmitEnumNaN.js	New baseline showing correct NaN/Infinity emission
testdata/baselines/reference/compiler/declarationEmitEnumNaN.types	New types baseline
testdata/baselines/reference/compiler/declarationEmitEnumNaN.symbols	New symbols baseline