fix(javascript): keep exact empty require paths and request fields

Migrate the remaining `""`-sentinel consumers from #783 to the nullable
`semanticStaticPropertyKey`: CommonJS module origins
(`require("m")['']`), require destructuring (`const {'': a} =
require("m")`), and request body fields (`{ '': value }`). Dynamic keys
still produce no link or field. API selectors that compare against known
names are unchanged.

Fixes #783

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/domain/javascriptSemanticAnalysis.empty_keys.test.ts

@@ -55,3 +55,51 @@ it("retains exact empty method names and environment keys", () => {
     { kind: "environment", key: null, resolution: "partial" },
   ]);
 });
+
+it("retains exact empty require paths without dynamic-key links", () => {
+  const ir = analyzeJavaScriptSemantics(`
+    const { '': fromPattern } = require("./table.js");
+    const fromMember = require("./table.js")[''];
+    const { [key]: dynamicPattern } = require("./table.js");
+    const dynamicMember = require("./table.js")[key];
+    module.exports.root = require("./table.js")[''];
+  `);
+  expect(
+    ir.moduleLinks.map(({ kind, importedName, localName, exportedName }) => ({
+      kind,
+      importedName,
+      localName,
+      exportedName,
+    })),
+  ).toEqual([
+    {
+      kind: "require",
+      importedName: "",
+      localName: "fromPattern",
+      exportedName: null,
+    },
+    {
+      kind: "require",
+      importedName: "",
+      localName: "fromMember",
+      exportedName: null,
+    },
+    {
+      kind: "commonjs-export",
+      importedName: "",
+      localName: null,
+      exportedName: "root",
+    },
+  ]);
+});
+
+it("retains exact empty request field names without dynamic fields", () => {
+  const ir = analyzeJavaScriptSemantics(`
+    fetch("https://example.test", { '': value, [key]: 1, body: "x" });
+  `);
+  expect(
+    ir.requestOperations.flatMap(({ fields }) =>
+      fields.map(({ name }) => name),
+    ),
+  ).toEqual(["", "body"]);
+});

src/domain/javascriptSemanticDataEffects.ts

@@ -405,8 +405,8 @@ const requestFields = (
     if (!t.isObjectProperty(property)) return [];
     // `{[key]: 1}` sends no knowable field name; reporting `key` would invent
     // a request field that may not exist.
-    const name = semanticStaticPropertyName(property.key, property.computed);
-    if (name.length === 0) return [];
+    const name = semanticStaticPropertyKey(property.key, property.computed);
+    if (name === null) return [];
     return [
       {
         name,

src/domain/javascriptSemanticProjection.ts

@@ -25,10 +25,7 @@ import {
   range,
   stringValue,
 } from "./javascriptStaticAnalysisHelpers.js";
-import {
-  semanticStaticPropertyKey,
-  semanticStaticPropertyName,
-} from "./javascriptAstValues.js";
+import { semanticStaticPropertyKey } from "./javascriptAstValues.js";
 
 interface CollectCallableInput {
   readonly node: t.Node;
@@ -181,8 +178,8 @@ const semanticModuleOrigin = (
     const nested = t.isNode(node.object)
       ? semanticModuleOrigin(node.object, projection, state)
       : undefined;
-    const member = semanticStaticPropertyName(node.property, node.computed);
-    return nested === undefined || member === ""
+    const member = semanticStaticPropertyKey(node.property, node.computed);
+    return nested === undefined || member === null
       ? undefined
       : { ...nested, importedPath: [...nested.importedPath, member] };
   }
@@ -341,8 +338,8 @@ const requirePatternBindings = (
   if (t.isObjectPattern(pattern))
     return pattern.properties.flatMap((property) => {
       if (t.isRestElement(property)) return [];
-      const name = semanticStaticPropertyName(property.key, property.computed);
-      return name === ""
+      const name = semanticStaticPropertyKey(property.key, property.computed);
+      return name === null
         ? []
         : requirePatternBindings(property.value, [...path, name]);
     });