fix(go): resolve chained factory-function calls New().Method() (#750) (#760)

* fix(go): resolve chained factory-function calls New().Method() (#750)

A Go call through a chained factory function — `New().Method()`,
`With(cfg).Build()` — dropped the receiver to a bare method name, which then
attached to a same-named method on an unrelated type (a wrong edge) or didn't
resolve. Ports the #645/#608 mechanism for Go's bare-factory receivers:

- Part 1: capture Go return types; a pointer `*Foo` -> `Foo`, a multi-return
  `(*Foo, error)` -> its first result, qualified `pkg.Foo` -> `Foo`.
- Part 2: encode a bare-factory chain (`New().Method`), gated to an `identifier`
  receiver so instance chains (`obj.Method().Other()`) keep bare-name.
- Part 3: matchDottedCallChain bare-inner Go branch looks up the FUNCTION's
  return type, then resolves+validates the method on it. Wired into the
  conformance pass so a method promoted from an embedded struct (`type Widget
  struct{ Base }` -> the existing `extends` edge) resolves. FALLBACK: when the
  inner isn't a resolvable function (a package-level VARIABLE holding a function
  value, e.g. gin's `engine()`), fall back to bare-name so the edge isn't dropped.

Validated: synthetic decoy + args + multi-return + embedded-conformance + absent
safety tests (4/4); full suite green. Real-repo A/B on gin (99 .go): pre-fallback
-40 = 25 wrong self-loops removed (good) + 15 correct `Engine::ServeHTTP` dropped
(gin's ginS variable-factory `engine()`); the fallback recovers the 15. gin A/B
re-confirm with the fallback is PENDING (local index flakiness, not a code issue).
EXTRACTION_VERSION 11 -> 12.

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

* fix(go): stop the chained-call fallback from looping the batched resolver

The Go variable-inner fallback (for chains like `engine().ServeHTTP()` whose
inner is a package-level var, not a factory function) resolved the method via
a synthetic bare-name ref and propagated THAT ref as `.original`. Its
`referenceName` was the bare `ServeHTTP`, not the stored `engine().ServeHTTP`,
so `resolveAndPersistBatched`'s keyed `deleteSpecificResolvedReferences` no-oped,
the offset-0 batch never drained, and the loop re-resolved + re-inserted the
same rows forever — a runaway that grew a 99-file repo (gin) to 5,050,206 edges
/ 1.4 GB before filling the disk.

- name-matcher.ts: tie the bare-name match back to the original `ref` so the
  batch-cleanup delete matches the stored row and the loop drains.
- index.ts: add a non-progress guard to resolveAndPersistBatched — if the
  unresolved_refs table doesn't shrink after a batch, stop instead of growing
  the graph without bound (defense-in-depth for any future keyed-delete mismatch).
- resolution.test.ts: regression test for the variable-inner chain — asserts the
  fallback edge resolves AND the edge count stays bounded (no explosion).

gin A/B (post-fix): db 5.8 MB / 3,699 calls edges; net-zero unique-edge diff vs
main (the fallback recovers the dropped edges, adds no wrong ones). Full suite green.

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

---------

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

CHANGELOG.md

@@ -29,6 +29,7 @@ and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ### Fixes
 
+- Go method calls made through a chained factory function now resolve to the correct type. A call like `New().Method()` used to drop the receiver, so the chained method attached to a same-named method on an unrelated type — or didn't resolve. CodeGraph now captures Go return types (a pointer `*Foo` resolves to `Foo`, and a multi-return `(*Foo, error)` to its first result), infers the chained receiver's type from what the factory function returns, and resolves the method on it — including methods promoted from an embedded struct — creating the edge only when the type or an embedded type genuinely has the method. Existing Go indexes should be re-indexed (`codegraph index -f`) to benefit. (#750) (Go)
 - Rust method calls made through a chained associated function now resolve to the correct type. A call like `Foo::new().bar()` or `Foo::with(cfg).build()` used to drop the receiver, so the chained method silently attached to a same-named method on an unrelated type — or didn't resolve. CodeGraph now captures Rust return types (`-> Self` resolves to the implementing type), infers the chained receiver's type from what the associated function returns, and resolves the method on it — including methods provided by a trait the type implements (via the new `impl Trait for Type` relationships) — creating the edge only when the type or one of its traits genuinely has the method. Existing Rust indexes should be re-indexed (`codegraph index -f`) to benefit. (#750) (Rust)
 - Chained method calls now resolve when the chained method is **inherited from a superclass or declared on an interface/protocol** the receiver's type conforms to — for example a call on a sealed-subclass instance (`Either.Right(x).combine(...)`) that invokes a method defined on its parent type. Previously these chains found no caller edge even though the factory's type was known, so the call was invisible to callers, impact, and trace. CodeGraph now walks the type's supertypes (its `extends` / `implements` relationships) to find the method, creating the edge only when a supertype genuinely declares it (so a wrong inference still produces no edge). This makes Java, Kotlin, and C# factory and fluent chains more complete. Existing indexes should be re-indexed (`codegraph index -f`) to benefit. (#750)
 - Swift method calls made through a static factory, fluent chain, or constructor now resolve to the correct class. A call like `Foo.make().draw()` or `Foo().draw()` used to drop the receiver, so the chained method silently attached to a same-named method on an unrelated class — or didn't resolve at all. CodeGraph now captures Swift return types and infers the chained receiver's type from what the inner call returns (or the constructed type), creating the edge only when that class genuinely has the method (so a wrong inference produces no edge instead of a misleading one). Existing Swift indexes should be re-indexed (`codegraph index -f`) to benefit. (#750) (Swift)