fix: Windows evaluating text on copy (#9293)

Author: Hona

packages/opencode/src/cli/cmd/tui/util/clipboard.ts

@@ -125,9 +125,25 @@ export namespace Clipboard {
     if (os === "win32") {
       console.log("clipboard: using powershell")
       return async (text: string) => {
-        // need to escape backticks because powershell uses them as escape code
-        const escaped = text.replace(/"/g, '""').replace(/`/g, "``")
-        await $`powershell -NonInteractive -NoProfile -Command "Set-Clipboard -Value \"${escaped}\""`.nothrow().quiet()
+        // Pipe via stdin to avoid PowerShell string interpolation ($env:FOO, $(), etc.)
+        const proc = Bun.spawn(
+          [
+            "powershell.exe",
+            "-NonInteractive",
+            "-NoProfile",
+            "-Command",
+            "[Console]::InputEncoding = [System.Text.Encoding]::UTF8; Set-Clipboard -Value ([Console]::In.ReadToEnd())",
+          ],
+          {
+            stdin: "pipe",
+            stdout: "ignore",
+            stderr: "ignore",
+          },
+        )
+
+        proc.stdin.write(text)
+        proc.stdin.end()
+        await proc.exited.catch(() => {})
       }
     }