Use UserConfigurations everywhere

[frogr]

Goal
Build the file transformation system that applies configuration changes across the entire codebase.
Tasks

• Create base transformer class
• Build Ruby file transformer (class names, modules, constants)
• Build view file transformer (app name, navigation, branding)
• Build stylesheet transformer (colors, CSS custom properties)
• Build configuration file transformer (Stripe keys, app settings)
• Create main generator that orchestrates all transformations
• Build CLI command bin/regenerate_app

File Transformations

Ruby files: Update class names, module names, constants
View files: Update app name in titles, navigation, footers
Stylesheets: Replace color values, update CSS custom properties
Config files: Update Stripe keys, app name in configs
Template files: Generate new content from ERB templates

Example Transformations

# Before
class HubController < ApplicationController
  
# After (when app_name = "MyStartup")  
class MyStartupController < ApplicationController

<!-- Before -->
<title>Hub - Ship faster</title>

<!-- After -->
<title>MyStartup - Ship faster</title>

Ruby files get class/module names updated correctly
View files show new app name throughout
Stylesheets use new color scheme
CLI command transforms entire app successfully
Transformations are idempotent (can run multiple times)