refactor: update site URL to be single source of truth (#143)

* wip: astro config to use .ts instead of .mjs

* fix: remove invalid prop in astro config

* refactor: single source of truth for site url

* refactor: make minor updates due to astro.config.ts

---------

Co-authored-by: satnaing <satnaingdev@gmail.com>

src/config.ts

@@ -1,7 +1,7 @@
 import type { Site, SocialObjects } from "./types";
 
 export const SITE: Site = {
-  website: "https://astro-paper.pages.dev/",
+  website: "https://astro-paper.pages.dev/", // replace this with your deployed domain
   author: "Sat Naing",
   desc: "A minimal, responsive and SEO-friendly Astro blog theme.",
   title: "AstroPaper",