Report on code attempting to set image quality for VIP Go File service to 100

We might want to start with something simple, prone to false positives. Eg.: reporting a Warning on every `$var['quality'] = 100;` or `$var['quality'] = '100'`.

Start by reviewing the existing PHP_CodeSniffer rules and their tests in VIP-Coding-Standards to find the pattern for reporting assignment warnings. Implement coverage for PHP code assigning 100 or '100' to a quality array key, including the stated false-positive-prone cases. Done means the rule reports those assignments consistently and the relevant tests pass.

Written by the indexing model from the issue text.