Send chat message to Khoj web app via url query param

- This allows triggering khoj chat from the browser addressbar
- So now if you add Khoj to your browser bookmark with
  - URL: https://app.khoj.dev/?q=%s
  - Keyword: khoj

- Then you can type "khoj what is the news today" to trigger Khoj to
  quickly respond to your query. This avoids having to open the Khoj web
  app before asking your question

src/interface/web/app/page.tsx

@@ -22,6 +22,7 @@ import { getIconFromIconName } from "@/app/common/iconUtils";
 import { AgentData } from "@/app/agents/page";
 import { createNewConversation } from "./common/chatFunctions";
 import { useIsMobileWidth } from "./common/utils";
+import { useSearchParams } from "next/navigation";
 
 interface ChatBodyDataProps {
     chatOptionsData: ChatOptions | null;
@@ -51,6 +52,14 @@ function ChatBodyData(props: ChatBodyDataProps) {
     const [agentIcons, setAgentIcons] = useState<JSX.Element[]>([]);
     const [agents, setAgents] = useState<AgentData[]>([]);
     const [showLoginPrompt, setShowLoginPrompt] = useState(false);
+    const searchParams = useSearchParams();
+    const queryParam = searchParams.get("q");
+
+    useEffect(() => {
+        if (queryParam) {
+            setMessage(decodeURIComponent(queryParam));
+        }
+    }, [queryParam]);
 
     const onConversationIdChange = props.onConversationIdChange;