feat: Overhauled base template

@types/fastify/index.d.ts

@@ -1,16 +1,11 @@
+import { SanitizedUser } from "#/db/types/users";
 import "fastify";
 
 declare module "fastify" {
   interface Session {
-    account: { // TODO: Type
-      userId: number;
-      username: string;
-      authenticated: boolean;
-    };
-
+    account: SanitizedUser;
     success?: string;
     error?: string;
-
     loginRedirectUri?: string;
   }
 }