docs: add getting started vignette

[akselthomsen]

Pull request

Closes #28

Summary

Add a getting started vignette that walks through the full component workflow: retrieve, render, evaluate, author custom components, validate code, and test with coverage.

Changes Made

• Add vignettes/mighty-component.Rmd covering all key APIs
• Update .Rbuildignore and .gitignore for vignette build artifacts

Testing

• rcmdcheck::rcmdcheck() passes with 0 errors, 0 warnings, 0 notes
• pkgdown::build_site() builds successfully
• Vignette renders correctly with all code chunks executing

Checklist

• Code changes have been tested
• Documentation has been updated, if applicable
• All automated tests pass
• Coding style and naming conventions have been followed
• The PR is ready for review and merge

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[github-actions]

Code coverage

Name	Coverage (%)
mighty.component	100
R/component.R	100
R/custom_r.R	100
R/mighty_component_rendered.R	100
R/mighty_component_test.R	100
R/mighty_component.R	100
R/standard.R	100
R/utils-validation.R	100
R/validate_component_code.R	100
R/validate_implicit_join.R	100

[github-actions]

Github pages

Review the pkgdown webpage for the PR here