Migrate bookkeeping lookup mount to React on Rails

[justin808]

Summary of the problem

hcb already uses react-rails, but that leaves the app on an older Rails + React integration path while newer maintenance and documentation effort is concentrated around React on Rails and Shakapacker.

I maintain both react-rails and react_on_rails, and for incremental Rails + React work I recommend moving toward React on Rails because it is the better-supported path going forward.

This PR is intentionally small. It converts one admin mount (bookkeeping/StripeChargeLookup) first so the app can prove a safe coexistence path before touching any broader frontend architecture.

Background docs:

• https://www.reactonrails.com/
• https://www.shakapacker.com/

Describe your changes

This keeps the rest of the app untouched and only migrates the bookkeeping lookup mount.

Changes in this slice:

• add the react_on_rails gem and JS package
• register BookkeepingStripeChargeLookup in the existing JS bundle
• swap the bookkeeping view from react-rails to an explicit react_on_rails_component helper
• preserve the legacy react_component(...) behavior for the many remaining react-rails mounts so both integrations can coexist safely during an incremental migration
• add a focused controller spec covering the new mount contract

Why this is better:

• it gives the app a supported migration path away from react-rails without forcing a full rewrite
• it makes the mount boundary more explicit and easier to evolve route by route
• it keeps future React on Rails / Shakapacker documentation and upgrade guidance applicable to the app

Local validation:

• repo Dockerfile build succeeds
• yarn build
• yarn build:css
• bundle exec rspec spec/controllers/admin_controller_bookkeeping_spec.rb
• bundle exec rubocop app/helpers/react_on_rails_migration_helper.rb config/initializers/react_on_rails.rb config/initializers/react_on_rails_helper_override.rb spec/controllers/admin_controller_bookkeeping_spec.rb

Asset-level comparison in the same Docker image:

• bundle.js: 2,739,714 -> 2,754,760 bytes (+15,046)
• yarn build: 10,035 ms -> 9,101 ms

So this first slice adds a small amount of bootstrap code, but it does not introduce a build-time regression, and the primary win is maintainability plus a cleaner forward migration path.

[garyhtou]

Hey Justin! Great to hear from you 😊!

I'll give this a read next week—let me know once this is ready for review.

[justin808]

Ready for review. I reran the slice in the repo documented Docker Compose path: docker compose run --rm -e RAILS_ENV=test web bundle exec rails db:test:prepare, docker compose run --rm -e RAILS_ENV=test web bundle exec rspec spec/controllers/admin_controller_bookkeeping_spec.rb, plus yarn build, yarn build:css, and focused RuboCop. The main value is still the safe coexistence path: one admin-owned mount moves to React on Rails without forcing a broader frontend rewrite.