test(acp): pin Windows-native snapshot paths

packages/support/acp-snapshot/tests/suite.spec.ts

@@ -18,6 +18,7 @@ import {
   refreshFixtureReplacements,
   restorePinnedToolSchemas,
   stabilizeRefreshLog,
+  stdoutGoldenVariants,
   unknownToolCallIds,
 } from '../src/suite.ts'
 
@@ -189,6 +190,31 @@ describe('childFixturePaths', () => {
   })
 })
 
+describe('stdoutGoldenVariants', () => {
+  const scenario: Scenario = {
+    name: 'windows-native',
+    hasModelTurn: true,
+    recorded: true,
+    pinsNativeWindowsStdout: true,
+  }
+
+  it('adds the native sidecar after the shared golden on Windows', () => {
+    expect(stdoutGoldenVariants(scenario, 'win32')).toEqual([
+      { file: 'stdout.golden.jsonl', cwdPathMode: 'canonical' },
+      { file: 'stdout.golden.windows.jsonl', cwdPathMode: 'native' },
+    ])
+  })
+
+  it('keeps only the shared golden on other platforms or without the declaration', () => {
+    expect(stdoutGoldenVariants(scenario, 'linux')).toEqual([
+      { file: 'stdout.golden.jsonl', cwdPathMode: 'canonical' },
+    ])
+    expect(stdoutGoldenVariants({ ...scenario, pinsNativeWindowsStdout: false }, 'win32')).toEqual([
+      { file: 'stdout.golden.jsonl', cwdPathMode: 'canonical' },
+    ])
+  })
+})
+
 describe('fixtureContext', () => {
   it('reads the fixture header id and cwd', () => {
     const ctx = fixtureContext('{"type":"session","id":"abc","cwd":"/rec"}\n{"type":"turn/start"}\n')