fix(retrieval): run in-process when pipes are forbidden

The Codex sandbox on Windows denies the pipes that the daemon and worker
process use, so searches waited 120 seconds and then failed. Detect that and
run the search in-process.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

shared/retrieval/server.py

@@ -11,6 +11,7 @@ import multiprocessing
 from multiprocessing import AuthenticationError
 from multiprocessing.connection import Client, Listener
 import os
+import queue
 from pathlib import Path
 import re
 import sqlite3
@@ -573,7 +574,23 @@ class Index:
             return result
 
 
+def pipes_available() -> bool:
+    """Sandboxes such as Codex on Windows forbid the pipes that the daemon and worker process need."""
+    try:
+        first, second = multiprocessing.Pipe()
+    except PermissionError:
+        return False
+    first.close()
+    second.close()
+    return True
+
+
 def run_direct(action: str, root: Path, data_dir: Path, model_cache: Path, query: str | None, top_k: int):
+    if not pipes_available():
+        # ponytail: in-process fallback has no worker timeout; the client's own command timeout still applies.
+        output = queue.Queue(1)
+        run_action(action, root, data_dir, model_cache, query, top_k, output)
+        return output.get()[1]
     output = multiprocessing.Queue(1)
     worker = multiprocessing.Process(target=run_action, args=(action, root, data_dir, model_cache, query, top_k, output))
     worker.start()
@@ -614,7 +631,7 @@ def main():
         parser.error("search requires --query")
     root = args.root.resolve()
     data_dir.mkdir(parents=True, exist_ok=True)
-    result = try_daemon(root, data_dir, model_cache, args.action, args.query, args.top_k)
+    result = try_daemon(root, data_dir, model_cache, args.action, args.query, args.top_k) if pipes_available() else None
     if result is None:
         result = run_direct(args.action, root, data_dir, model_cache, args.query, args.top_k)
     print(json.dumps(result, ensure_ascii=False))