Enum members are no longer registered as bare global constants. They are
held in a type-keyed reverse index (member name -> list of declaring
enum, ordinal, declaration order), so two enums may share a member name
without colliding in the global scope.
A bare member reference resolves by a fixed cascade:
1. a real symbol of that name wins (backwards compatible);
2. otherwise the expected type at the use site selects the enum;
3. otherwise a single unique candidate is accepted.
When a bare member is ambiguous and no type context is available, this is
now a hard error that names the declaring enums and tells the user to
qualify it as <EnumType>.Member, replacing the previous last-wins
warning. The separate duplicate-member warning channel is removed.
Expected-type context is supplied at every site that knows its target
type without changing the AnalyseExpr signature: variable/field/element
assignment (static, dynamic, open and multi-dimensional arrays, plus
implicit-Self and default-property writes), pointer-target writes, case
values and ranges, set elements and ranges, the `in` left operand, for
loop bounds, standalone and method call arguments (including
implicit-Self, qualified, metaclass and constructor calls), procedural-
type indirect-call arguments, and function results via Result and Exit.
Qualified forms (TEnum.Member, Unit.Member, Unit.TEnum.Member) continue
to resolve unchanged.
Tests cover each context above plus the ambiguity error, in both the
semantic/IR suite and the end-to-end suite.
3db2476983