test(all): CI check to make sure description mentions every changed file

[iswheeler]

Description

This PR adds a check so all PRs are required to list every file changed in the description. This will help contributors avoid pushing extra files accidentally by requiring them to acknowledge all changed files.

Type of Change

• New feature (feat)
• Bug fix (fix)
• Refactor / code improvement
• Dependency / build update
• Documentation
• Other (explain)

Changed Files

(Please list all files you changed, each with a description of what you changed and why.)
Tip: see a list of everything you changed on the "Files changed" tab

• check-description.yaml
  • CI routine to check if the name of each changed file is present in the PR description
• check-target.yaml
  • Added newline at end of file
• pr_description_check.py
  • Python script run by check-description.yaml to analyze PR changes and description

Related Issues

Does your code rely on another PR

No

Testing Done

Flutter:

• Tested on:
  • iOS Simulator
  • Android Emulator
  • Physical device
  • N/A (no Flutter code was changed)

Screenshots / Demo (if UI or notification change)

Checklist

• Commit messages follow Conventional Commits
• PR title follows [type](scope): short description
• PR target branch is not main and is our current working update branch (e.g. maizebus2.1)
• No print() / debugPrint() / console.log() left in production code
• Secrets / keys not committed