feat: add update notification to CLI for available package updates

[smoratino-apogea]

Add update notification to CLI

Description:

Summary

Adds a non-blocking update notifier to the thatopen CLI. When an outdated version is installed, users will see a notice at the end of any command's output prompting them to update.

What changed

• On every CLI invocation, a background fetch request checks the latest published version of thatopen-services on the npm registry.
• If the installed version differs from the latest, a warning message is printed after the command completes (via process.on('exit')), so it never interrupts normal output.
• The request has a 3-second timeout (AbortSignal.timeout) and fails silently — no network access or registry errors will ever affect CLI behaviour.

Example output

  ⚠ Update available: 0.12.0 → 0.13.1
  Run "npm install -g thatopen-services@latest" to update.

Notes

• No new dependencies added.
• Uses native fetch (available since Node 18+).
• Version comparison is a simple string equality check. Since the CLI is a globally installed tool and this only compares the published latest tag, this is sufficient for the intended use case.