Fix logout redirect to 0.0.0.0 instead of configured BASE_URL

Closes #113

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/api/auth/logout/route.ts

@@ -1,6 +1,7 @@
 import { NextRequest, NextResponse } from "next/server";
 import { getAuth } from "@/src/lib/auth-server";
 import { checkSameOrigin } from "@/src/lib/auth";
+import { config } from "@/src/lib/config";
 import { headers } from "next/headers";
 
 export const dynamic = "force-dynamic";
@@ -10,5 +11,5 @@ export async function POST(request: NextRequest) {
   if (originCheck) return originCheck;
 
   await getAuth().api.signOut({ headers: await headers() });
-  return NextResponse.redirect(new URL("/login", request.url));
+  return NextResponse.redirect(new URL("/login", config.baseUrl));
 }