fix(extraction/ruby): build receiver.method calls so instance calls resolve (#1110) (#1111)

The Ruby extractor dropped the method name from a `receiver.method` call:
`lg.log()` was recorded as a call to `lg` (the bare receiver), which
matches no symbol, so the reference resolved to nothing and no method
edge was ever produced. A Ruby method invoked through a receiver had no
recorded callers and was invisible to impact/blast-radius and explore
flow traces. This is the Ruby-specific blocker noted in #1108 — that
local-variable type-inference fix couldn't help Ruby because the call
reference itself was missing.

extractCall recognized receiver-bearing calls by the `object`/`name`/
`function` fields other grammars use; tree-sitter-ruby's `call` node uses
`receiver` + `method`, so it fell through to the generic fallback that
takes the first named child (the receiver) as the callee. Handle Ruby
`call`/`method_call` explicitly: build `receiver.method`, keep bare
`foo(...)` as the method name, emit `Foo.new` as an `instantiates` ref,
and give a capitalized (constant) receiver a `references` edge so a class
used only via its class methods still records a dependent.

With this plus #1108, `lg = Logger.new; lg.log` resolves `lg.log` to
`Logger#log`, and the two-file same-name case is same-file-correct
(#1079). Adds Ruby to the local-variable inference test matrix plus a
focused test asserting `Foo.new` stays an instantiation.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -12,6 +12,7 @@ and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 ### New Features
 
 - Method calls made through a local variable now resolve to the method in many more languages. When code does `const logger = new Logger(); logger.log();` (or the equivalent), CodeGraph infers the local variable's type from its declaration or initializer and links the call to the right method — so these calls now show up in callers, impact/blast-radius, and `codegraph_explore` flow traces instead of being dropped. Previously only C++ handled this; it now also covers TypeScript, JavaScript, Python, Java, C#, Kotlin, Swift, Go, Rust, Dart, Scala, and PHP. (#1108)
+- Ruby method calls made on a receiver (`logger.log`) now record an edge to the method. Previously the Ruby indexer kept only the receiver and discarded the method name, so a method called through a variable or object had no recorded callers and was missing from impact/blast-radius and flow traces; combined with the local-variable type inference above, `logger = Logger.new; logger.log` now links to `Logger#log`. Calls to a class method (`Foo.bar`) and object construction (`Foo.new`) are still recorded too. (#1110)
 
 ### Fixes