Address all Gemini code review feedback for SimpleFin integration

- Remove debug console.log statements from JavaScript controller
- Consolidate duplicate SimpleFin account creation methods into single method
- Refactor SimplefinItemsController to reduce complexity with helper methods
- Fix HTTParty thread-safety by moving SSL options to class level
- Remove redundant HTTParty options from individual requests
- Add proper error logging for invalid currency URIs
- Extract sync button path logic to AccountsHelper#sync_path_for method
- DRY up repeated subtype dropdown code with reusable partial and data structure

All SimpleFin tests passing (16/16). Code quality improvements maintain
backward compatibility while following Rails best practices.

app/javascript/controllers/account_type_selector_controller.js

@@ -5,7 +5,6 @@ export default class extends Controller {
   static values = { accountId: String }
 
   connect() {
-    console.log('Account type selector connected for account:', this.accountIdValue)
     // Show initial subtype dropdown based on current selection
     this.updateSubtype()
   }
@@ -16,8 +15,6 @@ export default class extends Controller {
     const container = this.subtypeContainerTarget
     const accountId = this.accountIdValue
     
-    console.log('Updating subtype for account:', accountId, 'Selected type:', selectedType)
-    
     // Hide all subtype selects
     const subtypeSelects = container.querySelectorAll('.subtype-select')
     subtypeSelects.forEach(select => {