feat: add core registry schemas

packages/core/src/hash.test.ts

@@ -17,10 +17,47 @@ describe("content hashing", () => {
     expect(left).toMatch(/^[a-f0-9]{64}$/);
   });
 
+  it("preserves own __proto__ keys while canonicalizing objects", () => {
+    const withProtoKey = JSON.parse('{"__proto__":{"x":1},"a":2}') as unknown;
+
+    expect(canonicalize(withProtoKey)).toBe('{"__proto__":{"x":1},"a":2}');
+    expect(hash(withProtoKey)).not.toBe(hash({ a: 2 }));
+  });
+
+  it("rejects hidden object keys that would be ignored by JSON rendering", () => {
+    const withSymbol = { a: 1, [Symbol("x")]: 2 };
+    const withHidden = { a: 1 };
+    Object.defineProperty(withHidden, "hidden", { value: 2, enumerable: false });
+
+    expect(() => canonicalize(withSymbol)).toThrow(/non-enumerable or symbol/);
+    expect(() => canonicalize(withHidden)).toThrow(/non-enumerable or symbol/);
+  });
+
+  it("rejects non-index array object keys that would be ignored by JSON rendering", () => {
+    const withStringKey = [1] as number[] & { extra?: number };
+    withStringKey.extra = 2;
+    const withSymbol = [1] as unknown[];
+    Object.defineProperty(withSymbol, Symbol("x"), { value: 2, enumerable: true });
+
+    expect(() => canonicalize(withStringKey)).toThrow(/non-index array/);
+    expect(() => canonicalize(withSymbol)).toThrow(/non-index array/);
+  });
+
+  it("renders the shortest round-trippable number literals without plus signs", () => {
+    expect(canonicalize([100, 1000, 11000, 123000, 1e20, 1e21, 0.000001, 0.0000001])).toBe(
+      "[100,1e3,11e3,123e3,1e20,1e21,1e-6,1e-7]",
+    );
+  });
+
   it("rejects values that are not JSON-safe", () => {
+    const sparse = Array<number>(3);
+    sparse[0] = 1;
+    sparse[2] = 3;
+
     expect(() => canonicalize({ date: new Date("2026-05-09T00:00:00Z") })).toThrow(
       /non-plain object/,
     );
     expect(() => canonicalize({ missing: undefined })).toThrow(/undefined/);
+    expect(() => canonicalize(sparse)).toThrow(/sparse array/);
   });
 });