Linter: add support for ignoring a rule on an entire file instead of just next or current line

E.g. in a class with `static` methods used to create an instance - I expect to be able to access private fields to assign them in this static factory functions without getting an error from the linter.

Currently, I have to mark each individual access. It can get quite verbose given multiple such static factory functions. In other parts of the code base - I want the rule - but in this file - it's fine for it to be completely disabled.

The issue names no implementation files or tests. Start by locating the existing linter handling for next-line and current-line ignores, then add coverage for file-wide suppression while confirming the existing narrower forms still work.

Written by the indexing model from the issue text.