chore: Remove Dockerfile and Docker CI job

[eshaffer321]

Summary

• Delete Dockerfile
• Remove docker job from .github/workflows/ci.yml

Why

This is a local single-user CLI tool — no containerized deployment exists or is planned. The Docker job was skipped on every PR anyway (only ran on pushes to main) and served no purpose.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 56.36%. Comparing base (fff532d) to head (dcb783d).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #18   +/-   ##
=======================================
  Coverage   56.36%   56.36%           
=======================================
  Files          43       43           
  Lines        4801     4801           
=======================================
  Hits         2706     2706           
  Misses       1931     1931           
  Partials      164      164           

Flag	Coverage Δ
unittests	56.36% <ø> (ø)

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

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.