feat!: replace auth with OIDC

Remove better-auth and replace it with OIDC

src/lib/components/lnv/sidebar/UserSidebar.svelte

@@ -0,0 +1,61 @@
+<script lang="ts">
+	import { onMount } from "svelte";
+	import SidebarHeader from "./SidebarHeader.svelte";
+	import Button from "$lib/components/ui/button/button.svelte";
+	import { getAuthURL, getOIDCUser } from "$lib/services/oidc";
+	import * as Avatar from "$lib/components/ui/avatar";
+
+	let user: any = $state(null);
+
+	onMount(() => {
+		if(!localStorage.getItem("lnv-token")) {
+			user = null;
+		} else {
+			user = JSON.parse(atob((localStorage.getItem("lnv-id") || "").split(".")[1]));
+		}
+	})
+</script>
+
+{#if !user}
+	<SidebarHeader>
+		User
+	</SidebarHeader>
+
+	<Button onclick={async () => {
+		const auth = await getAuthURL();
+		// localStorage.setItem("lnv-codeVerifier", auth.codeVerifier);
+		// localStorage.setItem("lnv-oidcstate", auth.state);
+		const popup = window.open(auth.url, "Login", "width=500,height=600");
+		window.addEventListener("message", async (e) => {
+			if(e.origin !== window.location.origin) return;
+
+			const { code, state } = e.data;
+			console.log("Received data from popup:", e.data);
+			if(!code || !state) {
+				console.error("Invalid response from popup");
+				return;
+			}
+			popup?.close();
+			if(state !== auth.state) {
+				alert("State mismatch. Please try again.");
+				return;
+			}
+
+			const token = await getOIDCUser(code, auth.codeVerifier);
+			localStorage.setItem("lnv-id", token.id_token);
+			localStorage.setItem("lnv-token", token.access_token);
+			localStorage.setItem("lnv-refresh", token.refresh_token);
+			user = JSON.parse(atob((localStorage.getItem("lnv-id") || "").split(".")[1]));
+		})
+	}}>Login</Button>
+{:else}
+	<SidebarHeader>
+		<Avatar.Root>
+			<Avatar.Image src={user.picture} />
+			<Avatar.Fallback>{user.preferred_username}</Avatar.Fallback>
+		</Avatar.Root>
+		{user.name || user.preferred_username}
+	</SidebarHeader>
+	<pre>{user.sub}</pre>
+	{JSON.stringify(user, null, 2)}
+{/if}