Exclude case_of targets from the per-file label map and apply the cross-file
_member_nids exclusion to all C# calls (not only new X()), so a bare call like
Delegate(t) no longer binds to a same-named enum case. Methods are method/
contains targets, not defines, so real call targets survive; fail-closed.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A C# enum's members got no graph node, so an enum case was invisible. Emit a member node
per enum_member_declaration with a case_of edge to the enum (mirroring the Java/Kotlin/Swift
enum handlers), deduped against a case-only sibling collision; explicit and implicit values
both work and no builtin types are fabricated.
