feat: enhance chat functionality with markdown support and default prompts

- Added support for rendering markdown in chat messages using ReactMarkdown with custom renderers.
- Integrated a default format prompt for the chat system, improving user experience by initializing with a predefined prompt.
- Updated the prompt generator to handle model selection more robustly, including loading states and fallback options for model selection.
- Enhanced UI components for better accessibility and user feedback during prompt generation.

components/chat/code-block.tsx

@@ -0,0 +1,45 @@
+import { Check, Copy } from "lucide-react";
+import { useState } from "react";
+import { Button } from "@/components/ui/button";
+
+interface CodeBlockProps {
+  language: string;
+  children: string;
+}
+
+export function CodeBlock({ language, children }: CodeBlockProps) {
+  const [copied, setCopied] = useState(false);
+
+  const handleCopy = () => {
+    navigator.clipboard.writeText(children);
+    setCopied(true);
+    setTimeout(() => setCopied(false), 2000);
+  };
+
+  return (
+    <div className="my-4 rounded-lg border bg-muted/50 overflow-hidden">
+      <div className="flex items-center justify-between px-4 py-2 bg-muted/80 border-b">
+        <span className="text-xs font-medium text-muted-foreground uppercase">
+          {language || "text"}
+        </span>
+        <Button
+          variant="ghost"
+          size="icon"
+          className="h-6 w-6 hover:bg-background/50"
+          onClick={handleCopy}
+          title="Copiar código"
+        >
+          {copied ? (
+            <Check className="h-3.5 w-3.5 text-green-500" />
+          ) : (
+            <Copy className="h-3.5 w-3.5 text-muted-foreground" />
+          )}
+        </Button>
+      </div>
+      <div className="p-4 overflow-x-auto">
+        <code className="text-sm font-mono whitespace-pre">{children}</code>
+      </div>
+    </div>
+  );
+}
+