Add AI chat feature

components/chat/chat-form.tsx

@@ -0,0 +1,34 @@
+import { useState, type SubmitEvent } from "react";
+import { Button } from "../ui/button";
+import { Textarea } from "../ui/textarea";
+import { ArrowUpIcon, SendIcon } from "lucide-react";
+
+interface ChatFormProps {
+  onMessage: (message: { text: string }) => void;
+  disabled?: boolean;
+}
+
+export function ChatForm({ onMessage, disabled }: ChatFormProps) {
+  const [text, setText] = useState("");
+
+  function handleSubmit(e: SubmitEvent<HTMLFormElement>) {
+    e.preventDefault();
+    if (!text.trim()) return;
+    setText("");
+    onMessage({ text });
+  }
+
+  return (
+    <form onSubmit={handleSubmit} className="flex gap-2">
+      <Textarea
+        name="text"
+        value={text}
+        onChange={(e) => setText(e.target.value)}
+        className="min-h-18"
+      />
+      <Button type="submit" disabled={disabled} size="icon-lg">
+        <ArrowUpIcon />
+      </Button>
+    </form>
+  );
+}