chore(toolkit): register valid message codes

[kaizencc]

Begins a registry of valid codes that are currently in use within the toolkit, and requires that only registered codes are used.

Checklist

• My code adheres to the CONTRIBUTING GUIDE and DESIGN GUIDELINES

---

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.79%. Comparing base (39e5578) to head (7ca354c).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #33160      +/-   ##
==========================================
+ Coverage   80.77%   80.79%   +0.01%     
==========================================
  Files         232      232              
  Lines       14110    14110              
  Branches     2453     2453              
==========================================
+ Hits        11398    11400       +2     
+ Misses       2432     2430       -2     
  Partials      280      280              

Flag	Coverage Δ
suite.unit	80.79% <ø> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
packages/aws-cdk	79.53% <ø> (+0.02%)	⬆️
packages/aws-cdk-lib/core	82.17% <ø> (ø)

[aws-cdk-automation]

AWS CodeBuild CI Report

• CodeBuild project: AutoBuildv2Project1C6BFA3F-wQm2hXv2jqQv
• Commit ID: 7ca354c
• Result: FAILED
• Build Logs (available for 30 days)

Powered by github-codebuild-logs, available on the AWS Serverless Application Repository