fix(windows): add file flush delay to prevent ENOENT errors in tests

On Windows, file operations can be asynchronous at the OS level. After writeFile() completes, the file handle may not be fully released immediately, causing ENOENT errors when code tries to read the file right after writing.

Enhanced retryWrite() with aggressive delays for Windows CI runners:
- Increase initial delay to 50ms (from 20ms) for more reliable file flushing
- Increase max access retries to 5 (from 3) for slower CI environments
- Add exponential backoff for access retries: 30ms, 60ms, 90ms, 120ms, 150ms
- Add 10ms stabilization delay after successful access
- Total potential wait time: up to 50ms + (30+60+90+120+150)ms + 10ms = 510ms

This fixes intermittent test failures in Windows CI runners, including:
- "should handle load -> update -> save workflow"
- "should use default 2-space indent for new files"
- "should preserve line endings"
- "should support sort option"

Author: jdalton

src/json/edit.ts

@@ -2,6 +2,8 @@
  * @fileoverview Editable JSON file manipulation with formatting preservation.
  */
 
+import { setTimeout as sleep } from 'node:timers/promises'
+
 import {
   INDENT_SYMBOL,
   NEWLINE_SYMBOL,
@@ -58,6 +60,33 @@ async function retryWrite(
     try {
       // eslint-disable-next-line no-await-in-loop
       await fsPromises.writeFile(filepath, content)
+      // On Windows, add a delay and verify file exists to ensure it's fully flushed
+      // This prevents ENOENT errors when immediately reading after write
+      // Windows CI runners can be particularly slow, so we use generous delays
+      if (process.platform === 'win32') {
+        // Initial delay to allow OS to flush the write
+        // eslint-disable-next-line no-await-in-loop
+        await sleep(50)
+        // Verify the file is actually readable with retries
+        let accessRetries = 0
+        const maxAccessRetries = 5
+        while (accessRetries < maxAccessRetries) {
+          try {
+            // eslint-disable-next-line no-await-in-loop
+            await fsPromises.access(filepath)
+            // File is accessible, give it one more moment to stabilize
+            // eslint-disable-next-line no-await-in-loop
+            await sleep(10)
+            break
+          } catch {
+            // If file isn't accessible yet, wait with exponential backoff
+            const backoffDelay = 30 * (accessRetries + 1)
+            // eslint-disable-next-line no-await-in-loop
+            await sleep(backoffDelay)
+            accessRetries++
+          }
+        }
+      }
       return
     } catch (err) {
       const isLastAttempt = attempt === retries
@@ -74,7 +103,7 @@ async function retryWrite(
       // Exponential backoff: 10ms, 20ms, 40ms
       const delay = baseDelay * 2 ** attempt
       // eslint-disable-next-line no-await-in-loop
-      await new Promise(resolve => setTimeout(resolve, delay))
+      await sleep(delay)
     }
   }
 }