Create a page or repo with various examples of custom rules for Oxlint JS Plugins

[connorshea]

Main constraints:

• Create various simple, but potentially-useful custom rules across various general categories (for example, banning a specific method from a specific module).
• Ensure they work, obviously.
• Add RuleTester tests for all of them, to show how to do this (especially important for usage with agents when they're generating custom rules, need to ensure the rules actually... work).

The goal here being that this'll help users (and their AI agents) create their own custom JS Plugins/rules.