fix(javascript)!: preserve property paths and uncertain slot presence

Use one explicit object/array slot model and JSON-pointer property identity across mutation analysis, return projection, and semantic graphs. Require observed presence for discriminants and resolve writes only through retained object or array receivers.

BREAKING CHANGE: projected return fields require explicit presence and semantic object operations carry full property paths.

src/domain/javascript/javascriptExportShapeComparisonSchemas.test.ts

@@ -71,6 +71,7 @@ it("parses projected fields into literal, union, or unknown values", () => {
     projectedExportReturnShapesSchema.safeParse(
       projectionWithField({
         path: "/kind",
+        presence: "present",
         state: "unknown",
         value: "invented",
         reason: "Dynamic property",
@@ -81,6 +82,7 @@ it("parses projected fields into literal, union, or unknown values", () => {
     projectedExportReturnShapesSchema.safeParse(
       projectionWithField({
         path: "/kind",
+        presence: "present",
         state: "union",
         value: ["success", "failure"],
         reason: null,
@@ -88,3 +90,16 @@ it("parses projected fields into literal, union, or unknown values", () => {
     ).success,
   ).toBe(true);
 });
+
+it("rejects return fields that omit slot presence", () => {
+  expect(
+    projectedExportReturnShapesSchema.safeParse(
+      projectionWithField({
+        path: "/kind",
+        state: "literal",
+        value: "result",
+        reason: null,
+      }),
+    ).success,
+  ).toBe(false);
+});