[Repo Assist] [TypeScript] Fix static class members not re-declaring class-level type parameters (fixes #3504)

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Summary

Fixes a TypeScript validity bug where static class members that use class-level type parameters produce TypeScript errors because the type parameters are not re-declared on the static method.

Closes #3504

Root Cause

In getMemberArgsAndBody (Fable2Babel.fs), the declaredTypeParams list controls which type parameters appear in the TypeScript method signature. For attached (class) members, the code previously excluded class-level type parameters (entGenParams) for all cases — both static and instance.

This is correct for instance methods: TypeScript instance methods can access class type params implicitly. But static methods cannot — TypeScript requires them to explicitly re-declare any class type params they use in their signature.

Example (before):

class MyList<TRaw> {
  instance(xs: FSharpList<TRaw>): void { ... }  // OK - TRaw inherited
  static checkLength(xs: FSharpList<TRaw>): int32 { ... }  // ERROR: TRaw undeclared
}

Example (after):

class MyList<TRaw> {
  instance(xs: FSharpList<TRaw>): void { ... }  // OK - TRaw inherited
  static checkLength<TRaw>(xs: FSharpList<TRaw>): int32 { ... }  // OK - TRaw declared
}

The Fix

In getMemberArgsAndBody, when computing declaredTypeParams for an attached member, check if kind = Attached(isStatic = true). If so, include entGenParams (the class-level type params) in declaredTypeParams alongside the method's own generic parameters.

The change is minimal — ~5 lines changed in getMemberArgsAndBody. No impact on JavaScript output (the typeParams path is TypeScript-only).

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