Bump TypeScript to 5.3 with verbatimModuleSyntax

This commit upgrades TypeScript to the latest version 5.3 and introduces
`verbatimModuleSyntax` in line with the official Vue guide
recommendatinos (vuejs/docs#2592).

By enforcing `import type` for type-only imports, this commit improves
code clarity and supports tooling optimization, ensuring imports are
only bundled when necessary for runtime.

Changes:

- Bump TypeScript to 5.3.3 across the project.
- Adjust import statements to utilize `import type` where applicable,
  promoting cleaner and more efficient code.

tests/checks/external-urls/StatusChecker/Requestor.ts

@@ -1,7 +1,7 @@
 import { retryWithExponentialBackOff } from './ExponentialBackOffRetryHandler';
-import { IUrlStatus } from './IUrlStatus';
-import { fetchFollow, IFollowOptions, DefaultFollowOptions } from './FetchFollow';
+import { fetchFollow, type IFollowOptions, DefaultFollowOptions } from './FetchFollow';
 import { getRandomUserAgent } from './UserAgents';
+import type { IUrlStatus } from './IUrlStatus';
 
 export function getUrlStatus(
   url: string,