fix: provider链白名单与实际config脱节导致模型无响应

- 原allowed仅4个provider(deepseek/volcengine/opencode-go*), config里只有deepseek(402欠费)→全链死
- 现按存活度排序: sense-nova(实测可用+tools支持)→deepseek→afw-proxy→ocg-key*
- 模型名: options.model优先, 否则取provider models字典第一个key

gateway/scripts/chat_bridge.py

@@ -96,11 +96,17 @@ _DEFAULT_MODELS = {
 def _build_chain() -> list[tuple[str, str, str]]:
     """Build (provider_key, base_url, model_name) in priority order.
 
-    优先用 deepseek（直连，稳定）→ volcengine（代理→Go）→ opencode-go（备用）。
+    2026-07-23 修复：原白名单只有 deepseek/volcengine/opencode-go*，
+    但 config 里只有 deepseek（402欠费）→ 全链死 → 模型无响应。
+    现按实际存活度排序：sense-nova（实测可用+支持tools）→ deepseek →
+    afw-proxy（本地代理，活着时优先）→ ocg-key*（Windows IP 当前403，恢复即可用）。
+    模型名：options.model 优先，否则取 provider models 字典第一个 key。
     """
-    allowed = ["deepseek", "volcengine", "opencode-go", "opencode-go-new"]
+    priority = ["sense-nova", "deepseek", "afw-proxy",
+                "ocg-key6", "ocg-key5", "ocg-key4", "ocg-key3", "ocg-key2", "ocg-key1",
+                "volcengine", "opencode-go", "opencode-go-new"]
     chain = []
-    for key in allowed:
+    for key in priority:
         prov = _PROVIDERS.get(key)
         if not prov:
             continue
@@ -109,7 +115,12 @@ def _build_chain() -> list[tuple[str, str, str]]:
         api_key = opts.get("apiKey", "")
         if not base or not api_key:
             continue
-        model = opts.get("model") or _DEFAULT_MODELS.get(key, "deepseek-v4-flash")
+        model = opts.get("model")
+        if not model:
+            _models = prov.get("models", {})
+            model = next(iter(_models.keys()), None) if _models else None
+        if not model:
+            model = _DEFAULT_MODELS.get(key, "deepseek-v4-flash")
         chain.append((key, base, model))
     return chain