fix(scala): resolve chained static-factory/apply calls Foo.create().bar() (#750) (#761)

Ports the #645 (C++) / #608 (PHP) chained-receiver mechanism to Scala. A call
whose receiver is itself a call — `Foo.create().bar()` (companion factory),
`Builder(cfg).bar()` (case-class apply), or a fluent chain — used to drop the
receiver to a bare `bar`, which name-matched a same-named method on an unrelated
type. The most common wrong edge was a stdlib `Option`/`Iterator` `.map`/`.flatMap`/
`.foreach` mis-attributed onto the project's own same-named class.

- scala.ts: `getReturnType` reads the `return_type` field — generic `List[Foo]`
  → container `List`, qualified `pkg.Foo` → `Foo`, `this.type` left undefined.
- tree-sitter.ts: re-encode `Foo.create().bar` when the inner call's receiver chain
  starts with a capital (companion factory / case-class apply); instance chains
  (`list.map().filter()`) stay bare.
- name-matcher.ts: `scala` joins the dotted-chain gate + CONSTRUCTS_VIA_BARE_CALL
  (case-class `apply` constructs the class); resolveMethodOnType validates, so a
  non-conventional `apply` returning another type yields no edge, not a wrong one.
- index.ts: `scala` joins CHAIN_LANGUAGES so trait-inherited methods resolve via
  the conformance second pass.

Validation: 4 synthetic tests (factory+decoy, case-class apply, trait conformance,
absent-method safety). Real-repo A/B on gatling (750 Scala files): +14 / -59 unique
edges — all corrections. The +14 are retargets (e.g. `HttpProtocolBuilder(cfg).baseUrl`
now resolves to HttpProtocolBuilder::baseUrl, not the same-named private BaseUrlSupport
helper); the -59 are wrong edges removed (stdlib Option/Iterator monad calls
mis-tied to the project's Validation::*, self-loops, decoy collisions) — zero genuine
factory chains dropped (verified: gatling has no real Validation.success().map() chains).
db stable at 40 MB. EXTRACTION_VERSION 12→13. Full suite green.

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

src/extraction/extraction-version.ts

@@ -21,4 +21,4 @@
  * turns the re-index hint into noise — keep it honest (see CLAUDE.md, "Honesty
  * in the product is load-bearing").
  */
-export const EXTRACTION_VERSION = 12;
+export const EXTRACTION_VERSION = 13;