fix(macho): recognize arm64_32 binaries

Fixes #6581

src/native/metadata/MachoImage.ts

@@ -156,6 +156,7 @@ export const readMachoImage = (bytes: Buffer): BinaryContainer => {
     [0x01000007, "amd64"],
     [12, "arm"],
     [0x0100000c, "arm64"],
+    [0x0200000c, "arm64_32"],
     [18, "ppc"],
     [0x01000012, "ppc64"],
   ]);

tests/acceptance/rustBinaryCli.test.ts

@@ -119,6 +119,39 @@ cliTest("returns null metadata when .dep-v0 is absent", async ({ cli }) => {
   );
 });
 
+cliTest(
+  "keeps arm64_32 in Rust CLI Evidence when dependency metadata is absent",
+  async ({ cli }) => {
+    const root = await createTestTempDirectory("rea-rust-arm64-32-");
+    const path = join(root, "watchos-object");
+    const bytes = createRustImage({
+      format: "macho",
+      omitSection: true,
+      includeRustc: false,
+    });
+    bytes.writeUInt32LE(0x0200000c, 4);
+    await writeFile(path, bytes);
+
+    const result = await cli.run({
+      arguments: ["inspect-rust-binary", path, "--json"],
+    });
+
+    expect(result.exitCode, result.stderr).toBe(0);
+    const evidence = toolContract("inspect_rust_binary").outputSchema.parse(
+      result.json,
+    );
+    expect(evidence.subject).toMatchObject({
+      format: "mach-o",
+      architecture: "arm64_32",
+    });
+    expect(rustBinarySchema.parse(evidence.normalized_result)).toMatchObject({
+      architecture: "arm64_32",
+      bits: 64,
+      auditable_metadata: null,
+    });
+  },
+);
+
 cliTest(
   "preserves an unknown cargo-auditable revision and reports its fallback",
   async ({ cli }) => {

tests/boundary/rust/rustBinaryImage.test.ts

@@ -70,6 +70,23 @@ it("reads a Mach-O __DATA,.dep-v0 section", () => {
   });
 });
 
+it("preserves the arm64_32 Mach-O CPU family when dependency metadata is absent", () => {
+  const bytes = createRustImage({
+    format: "macho",
+    omitSection: true,
+    includeRustc: false,
+  });
+  bytes.writeUInt32LE(0x0200000c, 4);
+
+  expect(readRustBinaryImage(bytes)).toMatchObject({
+    format: "macho",
+    architecture: "arm64_32",
+    bits: 64,
+    auditable_metadata: null,
+    rustc_commit: null,
+  });
+});
+
 it("ignores PE file-alignment padding after the dependency content", () => {
   const bytes = createRustImage({ format: "pe", includeRustc: false });
   const payloadBytes = rustDependencyPayload().length;