Update workflows, CODEOWNERS, and config files

[coliff]

Clarifies copilot instructions to avoid deprecated TypeScript features, and updates dependabot.yml to group GitHub Actions updates and limit open PRs. Adds a workflow for accessibility alt text checks and introduces a .npmrc file with lockfile version and registry settings.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (95e6a13) to head (1d78d2c).
⚠️ Report is 165 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #1759      +/-   ##
===========================================
+ Coverage   96.99%   100.00%   +3.00%     
===========================================
  Files           2         1       -1     
  Lines        1628         1    -1627     
  Branches      335         0     -335     
===========================================
- Hits         1579         1    -1578     
+ Misses         49         0      -49     

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[gemini-code-assist]

Code Review

This pull request introduces several excellent improvements to the repository's configuration. It updates the CODEOWNERS file, clarifies instructions for GitHub Copilot, and enhances the dependabot.yml configuration to group GitHub Actions updates, which will help reduce pull request noise. Additionally, it adds a .npmrc file to enforce lockfile version 3 and standardize the npm registry. I have one suggestion to further improve dependency management by enforcing exact versions in the new .npmrc file. Overall, these are great changes that follow best practices.