fix: tool call anchor & wire format, streaming chunk passthrough, WebUI narrow-screen, docs bilingual

internal/provider/provider.go

@@ -100,6 +100,43 @@ func (p *Provider) ModelByID(id string) *config.Model {
 	return nil
 }
 
+// ModelFor resolves the model name this provider should send upstream.
+// If the requested model is not owned by this provider (e.g. an AUTO chain
+// fallback), it returns this provider's highest-priority chat model instead.
+func (p *Provider) ModelFor(reqModel string) string {
+	if reqModel == "" || isAutoID(reqModel) {
+		return p.bestChatModel()
+	}
+	if p.ModelByID(reqModel) != nil {
+		return reqModel
+	}
+	return p.bestChatModel()
+}
+
+// bestChatModel returns the highest-priority chat-kind model of this source.
+func (p *Provider) bestChatModel() string {
+	bestID, bestPrio := "", -1
+	for _, m := range p.cfg.Models {
+		if m.Kind != "" && m.Kind != "chat" {
+			continue
+		}
+		if m.Priority > bestPrio {
+			bestPrio = m.Priority
+			bestID = m.ID
+		}
+	}
+	if bestID == "" && len(p.cfg.Models) > 0 {
+		bestID = p.cfg.Models[0].ID
+	}
+	return bestID
+}
+
+// IsAutoID reports whether s is an AUTO routing placeholder.
+func isAutoID(s string) bool {
+	s = strings.TrimSpace(s)
+	return s == "" || strings.EqualFold(s, "AUTO")
+}
+
 // Endpoint resolves the upstream chat path.
 func (p *Provider) Endpoint() string {
 	if p.cfg.Endpoint != "" {