fix: preserve unicode in Windows clipboard fallback (#388)

* fix: preserve unicode in Windows clipboard fallback

* fix: avoid Windows clipboard stdin codepage issues

* test: fix Windows clipboard temp path fixture

src/ink/termio/osc.ts

@@ -3,8 +3,10 @@
  */
 
 import { Buffer } from 'buffer'
+import { unlink, writeFile } from 'node:fs/promises'
 import { env } from '../../utils/env.js'
 import { execFileNoThrow } from '../../utils/execFileNoThrow.js'
+import { generateTempFilePath } from '../../utils/tempfile.js'
 import { BEL, ESC, ESC_TYPE, SEP } from './ansi.js'
 import type { Action, Color, TabStatusAction } from './types.js'
 
@@ -129,7 +131,7 @@ export async function tmuxLoadBuffer(text: string): Promise<boolean> {
  * Local (no SSH_CONNECTION): also shell out to a native clipboard utility.
  * OSC 52 and tmux -w both depend on terminal settings — iTerm2 disables
  * OSC 52 by default, VS Code shows a permission prompt on first use. Native
- * utilities (pbcopy/wl-copy/xclip/xsel/clip.exe) always work locally. Over
+ * utilities (pbcopy/wl-copy/xclip/xsel/PowerShell Set-Clipboard) always work locally. Over
  * SSH these would write to the remote clipboard — OSC 52 is the right path there.
  *
  * Returns the sequence for the caller to write to stdout (raw OSC 52
@@ -211,9 +213,32 @@ function copyNative(text: string): void {
       return
     }
     case 'win32':
-      // clip.exe is always available on Windows. Unicode handling is
-      // imperfect (system locale encoding) but good enough for a fallback.
-      void execFileNoThrow('clip', [], opts)
+      // Avoid piping non-ASCII text through the Windows stdin/codepage
+      // boundary. Write UTF-8 text to a temp file and let PowerShell read it
+      // directly as UTF-8 before calling Set-Clipboard.
+      void (async () => {
+        const tempPath = generateTempFilePath('openclaude-clipboard', '.txt')
+        const escapedTempPath = tempPath.replace(/'/g, "''")
+        try {
+          await writeFile(tempPath, text, { encoding: 'utf8' })
+          await execFileNoThrow(
+            'powershell',
+            [
+              '-NoProfile',
+              '-NonInteractive',
+              '-Command',
+              `$text = [System.IO.File]::ReadAllText('${escapedTempPath}', [System.Text.Encoding]::UTF8); Set-Clipboard -Value $text`,
+            ],
+            {
+              useCwd: false,
+              timeout: opts.timeout,
+              stdin: 'ignore',
+            },
+          )
+        } finally {
+          await unlink(tempPath).catch(() => {})
+        }
+      })().catch(() => {})
       return
   }
 }