A C# `foreach` loop variable had no binding in the method-scoped receiver
table, so a call on it (or a chain starting at it) never resolved across
files: `foreach (var a in agents.Values) a.look.Animate();` produced no edge.
The loop variable is now bound inside its loop: to its explicit type
(`foreach (Agent a in xs)`), or for `var` to what a class field or property
yields when iterated: the element of a `T[]` or of a sequence type, and a
dictionary's value or key type for `f.Values` / `f.Keys`. Iterating a
dictionary itself (KeyValuePair), nested collections, type parameters, and a
loop over a name that a local or parameter shadows stay untyped.
Closes#4420.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
(cherry picked from commit f101ad4913)
