Make the add-to-hosts-file regex stricter to avoid incorrect matches

[andrew-nowak]

What does this change?

There's a grep call in add-to-hosts-file which aims to prevent adding duplicate entries. Unfortunately the regex is naive so will match a domain even if it doesn't exist and is only a substring of an existing domain. For example, if we've already added api.media.local.dev-gutools.co.uk, then the command will not allow us to add media.local.dev-gutools.co.uk as that domain appears to already exist.

Improve the match with grep's extended regex to match the entire line, from IP address, delimiting whitespace to domain name and end-of-line marker. Now dev-nginx should correctly deduplicate entries.

How to test

Run add-to-hosts-file api.media.local.dev-gutools.co.uk then add-to-hosts-file media.local.dev-gutools.co.uk - you should not get a message that the entry already exists. (remember to clean up your /etc/hosts file afterwards!)

[Copilot]

Pull Request Overview

This PR fixes a bug in the add-to-hosts-file script where the grep regex was too permissive, causing false matches when checking for existing hosts file entries. The issue occurred when a domain was a substring of an already existing domain (e.g., media.local.dev-gutools.co.uk appearing to exist when only api.media.local.dev-gutools.co.uk was present).

• Replaces the naive grep pattern with a stricter extended regex that matches the complete line format
• Uses anchors and whitespace patterns to ensure exact domain matching rather than substring matching