fix(ops): English replies from English prompts and ROLE_SYSTEM.en

Detect language from user message before UI hint, load ops ROLE_SYSTEM.en.md when en, and wire user_text through WS/HTTP/worker paths.

Co-authored-by: Cursor <cursoragent@cursor.com>

runtime/lang.py

@@ -1,10 +1,39 @@
 from __future__ import annotations
 
+import re
 from typing import Any
 
+_CJK_RE = re.compile(r"[\u4e00-\u9fff\u3400-\u4dbf\uf900-\ufaff]")
 
-def resolve_runtime_lang(*, store: Any | None = None, hint: str | None = None) -> str:
-    """Resolve zh/en for agent runtime (WS, worker, HTTP share this helper)."""
+
+def detect_text_lang(text: str) -> str | None:
+    """Heuristic zh/en from user message; None if ambiguous."""
+    t = str(text or "").strip()
+    if not t:
+        return None
+    cjk = len(_CJK_RE.findall(t))
+    latin = sum(1 for ch in t if ch.isascii() and ch.isalpha())
+    if cjk >= 2 and cjk >= latin:
+        return "zh"
+    if latin >= 6 and latin > cjk * 2:
+        return "en"
+    return None
+
+
+def resolve_runtime_lang(
+    *,
+    store: Any | None = None,
+    hint: str | None = None,
+    user_text: str | None = None,
+) -> str:
+    """Resolve zh/en for agent runtime (WS, worker, HTTP share this helper).
+
+    User message language wins over UI hint so English prompts get English replies
+    even when the admin UI is still set to Chinese.
+    """
+    detected = detect_text_lang(user_text or "")
+    if detected in ("zh", "en"):
+        return detected
     raw = str(hint or "").strip().lower()
     if raw in ("zh", "en"):
         return raw
@@ -18,4 +47,4 @@ def resolve_runtime_lang(*, store: Any | None = None, hint: str | None = None) -
     return "zh"
 
 
-__all__ = ["resolve_runtime_lang"]
+__all__ = ["detect_text_lang", "resolve_runtime_lang"]