test(json): add Windows file readability delay after save operations

Add waitForFile() helper that adds a 50ms delay on Windows after save()
operations to ensure the file is readable before attempting to read it. This
addresses a test-level race condition where tests were failing intermittently
because they tried to read files immediately after writing, before Windows
had made them accessible.

Updated tests:
- should preserve line endings
- should support sort option
- should use default 2-space indent for new files

This complements the production code fix in retryWrite() by also ensuring
tests don't race against filesystem operations.

Author: jdalton

test/unit/json.test.ts

@@ -761,6 +761,13 @@ describe('json', () => {
   describe('EditableJson', () => {
     let testDir: string
 
+    // Helper to wait for file to be readable on Windows after write
+    const waitForFile = async () => {
+      if (process.platform === 'win32') {
+        await sleep(50)
+      }
+    }
+
     beforeEach(async () => {
       testDir = await mkdtemp(join(tmpdir(), 'editable-json-test-'))
     })
@@ -1070,6 +1077,7 @@ describe('json', () => {
         const instance = await EditableJson.load(filepath)
         instance.update({ newKey: 'newValue' })
         await instance.save()
+        await waitForFile()
 
         const content = await readFile(filepath, 'utf8')
         expect(content).toContain('\r\n')
@@ -1091,6 +1099,7 @@ describe('json', () => {
         })
 
         await instance.save({ sort: true })
+        await waitForFile()
 
         const content = await readFile(filepath, 'utf8')
         const keys = Object.keys(JSON.parse(content))
@@ -1116,6 +1125,7 @@ describe('json', () => {
         })
 
         await instance.save()
+        await waitForFile()
 
         const content = await readFile(filepath, 'utf8')
         expect(content).toBe('{\n  "key": "value"\n}\n')