Refs #39354 - Update RuboCop dependencies

[jakduch]

What changed

• update RuboCop from 1.56.x to 1.88.x
• update rubocop-performance from 1.5.x to 1.26.x
• migrate the RuboCop extensions to the current plugin configuration
• apply the behavior-preserving style updates required by the new cops

This removes RuboCop's < 3.0 restriction on unicode-display_width, allowing the generated Smart Proxy CI lockfile to align on the 3.x release used by the other Foreman projects.

Thor remains blocked

The thor part of #39354 cannot be resolved by bundle update: Facter 4.11.0 still declares thor >= 1.0.1, < 1.3 to retain Ruby 2.5 support. The upstream change to remove that restriction is still open in puppetlabs/facter#2751. Raising Thor in Smart Proxy before a compatible Facter release would make the bundle unsatisfiable, so this PR deliberately uses Refs rather than claiming to fix the whole issue.

Validation

• verified the new RuboCop releases support Smart Proxy's Ruby 3.0 minimum
• verified RuboCop 1.88 permits unicode-display_width >= 2.4, < 4.0
• checked the diff for whitespace errors
• checked Ruby syntax for every adjusted source file

The generated lockfile and RuboCop run will be validated by the upstream CI matrix.

AI assistance disclosure: This pull request was prepared with assistance from Codex 5.6 Sol High. The changes were reviewed by the author.