fix(providers): support anthropic proxy v1 endpoints

agent/anthropic_adapter.py

@@ -751,6 +751,9 @@ def build_anthropic_client(
     from httpx import Timeout
 
     normalized_base_url = _normalize_base_url_text(base_url)
+    if normalized_base_url:
+        import re as _re
+        normalized_base_url = _re.sub(r"/v1/?$", "", normalized_base_url.rstrip("/"))
     _read_timeout = timeout if (isinstance(timeout, (int, float)) and timeout > 0) else 900.0
     kwargs = {
         "timeout": Timeout(timeout=float(_read_timeout), connect=10.0),

agent/auxiliary_client.py

@@ -1144,7 +1144,8 @@ def _endpoint_speaks_anthropic_messages(base_url: str) -> bool:
     normalized = (base_url or "").strip().lower().rstrip("/")
     if not normalized:
         return False
-    if normalized.endswith("/anthropic"):
+    path = urlparse(normalized).path.rstrip("/")
+    if path.endswith("/anthropic") or path.endswith("/anthropic/v1"):
         return True
     hostname = base_url_hostname(normalized)
     if hostname == "api.anthropic.com":