feat: implement strict-client compatible streaming tool calls with index and add Vercel build troubleshooting guide.

internal/util/toolcalls.go

@@ -298,3 +298,20 @@ func FormatOpenAIToolCalls(calls []ParsedToolCall) []map[string]any {
 	}
 	return out
 }
+
+func FormatOpenAIStreamToolCalls(calls []ParsedToolCall) []map[string]any {
+	out := make([]map[string]any, 0, len(calls))
+	for i, c := range calls {
+		args, _ := json.Marshal(c.Input)
+		out = append(out, map[string]any{
+			"index": i,
+			"id":    "call_" + strings.ReplaceAll(uuid.NewString(), "-", ""),
+			"type":  "function",
+			"function": map[string]any{
+				"name":      c.Name,
+				"arguments": string(args),
+			},
+		})
+	}
+	return out
+}