muse-chat-api.py: Fix sidechat create URL race\n\nPoll for /thread/ URL up to 15s instead of fixed 5s sleep.\nWas capturing base URL before navigation settled.

bin/muse-chat-api.py

@@ -277,8 +277,18 @@ def cmd_sidechat_create(ws):
         print("ERROR: 'New side chat' button not found (sidebar may be closed)", file=sys.stderr)
         sys.exit(1)
     import time as _time
-    _time.sleep(5)
+    # Poll for URL to change to a thread URL (up to 15s)
+    # Fixed 2026-10-04: was sleeping 5s and reading once, often captured
+    # base URL before navigation settled.
+    url = None
+    for i in range(15):
+        _time.sleep(1)
         url = ev(ws, "window.location.href")
+        if url and "/thread/" in url:
+            break
+    if not url or "/thread/" not in url:
+        print(f"ERROR: Sidechat creation did not navigate to thread URL (got: {url})", file=sys.stderr)
+        sys.exit(1)
     print(f"Created: {url}")
     return url