Fix #665 (nested namespace bare-name → enclosing scope); complete #639

[nickna]

#665 — nested namespace member cannot reference an enclosing namespace's member by bare name

A function in a nested namespace could not reference a member of its enclosing namespace by bare (unqualified) name — rejected at type-check as Undefined variable in both modes. tsc accepts it (enclosing members are in lexical scope of nested bodies).

namespace O {
  function outerHelp() { return 7; }            // non-exported member of O
  export namespace I {
    export function f() { return outerHelp(); }  // bare ref to O.outerHelp
  }
}
console.log(O.I.f());   // tsc: 7 — now 7 in both modes

Root cause (type checker): CheckNamespace fully checks any nested namespace during the enclosing namespace's first pass (CollectNamespaceMemberType → recursive CheckNamespace), but member functions were only registered in the second pass — so nested bodies saw nothing. Fix: CheckNamespace now HoistFunctionDeclarations(ns.Members) before the first pass, mirroring the top-level hoisting order. (var/const/class/enum already resolved.)

Compiled codegen: a bare reference to a sibling/enclosing namespace object (A.g() from O.B.f, where A is O.A) type-checked but threw at runtime — namespace fields are keyed by full dotted path ($ns_O_A), so the simple name never matched. New CompilationContext.ResolveNamespaceField walks the current namespace path innermost→outermost (mirroring ResolveFunctionName), wired into both bare-variable sites (ILEmitter.Expressions + ExpressionEmitterBase) so the sync and state-machine paths stay in sync. Also covers new A.X() from a sibling namespace.

6 new both-mode tests (SharedTests/NamespaceTests.cs): issue repro, forward reference, enclosing class, sibling namespace, 3-level nesting, inner-shadows-outer.

#639 — branded-target collector with a generic-instantiation superclass

The substantive collector fix already landed on main (#655). This completes the issue's remaining minor/related note: the MutableClass branch of GetMemberType (signature-collection-time) walked frozen.Superclass with unsubstituted GetFieldTypes/GetMethods, surfacing an inherited generic-base member as the bare type parameter. Routed it through the existing substitution-aware ResolveClassMemberTypeSubstituted, unifying it with the frozen-instance path and the member-set collectors. Equivalent for a non-generic superclass; not independently observable (matches the issue's "transient" framing), validated by the full suite.

Follow-ups filed

• Type checker: a nested namespace member cannot reference its enclosing namespace by the enclosing namespace's own name #745 — a nested namespace cannot name its enclosing namespace by its own name (O.A.g() from inside O); the namespace self-binds only at the end of CheckNamespace.
• Interpreter: a nested namespace shadowing a same-named top-level namespace throws on bare reference (compiled mode is correct) #746 — the interpreter mis-resolves a nested namespace shadowing a same-named top-level namespace (compiled mode is correct).

Testing

• Full suite: 13033 passed / 0 failed.
• TSConformance subset (assignmentCompatibility + conditional) does not cover namespaces; the CollectAllInstanceMembers (branded-target member enumeration) doesn't walk a generic-instantiation superclass #639 refactor is provably equivalent for the non-generic case — skipped per the project's conformance-scope guidance.

Closes #665. Closes #639.