Update dependencies and project configuration

Add Nix flake support, update .gitignore to ignore SSL certs, upgrade
@types/bun and TypeScript versions, and update frontend SDK URLs in
index.html and sw.js to new API endpoints

server.ts

@@ -29,6 +29,12 @@ function getMimeType(filename: string): string {
 
 const server = Bun.serve({
   port: 5173,
+
+  // tls: {
+  //   key: Bun.file("./ssl/key.pem"),
+  //   cert: Bun.file("./ssl/cert.pem"),
+  // },
+
   async fetch(req) {
     const url = new URL(req.url);
     const pathname = url.pathname;