fix(javascript): converge cyclic aliases with explicit projection widening

Replace initializer-history and full-path enumeration with a finite projection
join at each source read. Retain conservative local returned-reference effects
and disclose precision loss through static, semantic and captured-web results.
Close full-binding callback cycles while preserving narrowed read semantics.

Fixes #4348
Fixes #5138
Refs #4349
Refs #4364

Co-authored-by: Kaoru0822 <208281322+kaoru0822-kitauji@users.noreply.github.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: Fuxuan-CN <3072252442@qq.com>

src/domain/javascript/javascriptReturnedReferenceCoverage.test.ts

@@ -0,0 +1,33 @@
+import { expect, it } from "vitest";
+
+import { analyzeJavaScriptSemantics } from "./javascriptSemanticAnalysis.js";
+import { analyzeJavaScriptStaticSource } from "./javascriptStaticAnalysis.js";
+import { RETURNED_REFERENCE_WIDENING_LIMITATION } from "./javascriptSemanticCoverage.js";
+
+it("preserves possible ambient effects and discloses projection widening in source coverage", () => {
+  const source = `
+    function expose() { return Map.prototype; }
+    let cursor = { target: expose };
+    function walk(flag) {
+      while (flag) cursor = cursor.next;
+      patch(cursor.target());
+    }
+    fetch('/preserved');
+    new Map().get('/candidate');
+  `;
+  const ir = analyzeJavaScriptSemantics(source);
+  expect(ir.coverage).toMatchObject({ status: "partial", omittedCount: 0 });
+  expect(ir.coverage.widenedReturnedReferences?.length).toBeGreaterThan(0);
+  expect(ir.limitations).toContain(RETURNED_REFERENCE_WIDENING_LIMITATION);
+  const facts = analyzeJavaScriptStaticSource(source);
+  expect(facts.limitations).toContain(RETURNED_REFERENCE_WIDENING_LIMITATION);
+  expect(facts.endpoints).toEqual(
+    expect.arrayContaining([
+      expect.objectContaining({ value: "/preserved", mechanism: "call:fetch" }),
+      expect.objectContaining({
+        value: "/candidate",
+        interpretation: "candidate",
+      }),
+    ]),
+  );
+});