Remove company information section from onboarding

Completely remove the enterprise/company information functionality from
the onboarding flow to simplify the user experience:

- Remove company information toggle section and form fields from view
- Delete unused Stimulus toggle controller (toggle_section_controller.js)
- Update onboarding controller to only process first/last name parameters
- Remove company_name from permitted parameters and validation logic
- Update tests to remove company name assertions and test cases
- Simplify onboarding to only collect essential personal information

The onboarding now focuses solely on collecting required first and last
names, providing a cleaner and faster user experience.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

app/javascript/controllers/toggle_section_controller.js

@@ -1,25 +0,0 @@
-import { Controller } from "@hotwired/stimulus"
-
-// Connects to data-controller="toggle-section"
-export default class extends Controller {
-  static targets = ["section", "icon"]
-  
-  connect() {
-    // Ensure the section starts hidden
-    this.sectionTarget.classList.add("hidden")
-  }
-  
-  toggle() {
-    const isHidden = this.sectionTarget.classList.contains("hidden")
-    
-    if (isHidden) {
-      // Show the section
-      this.sectionTarget.classList.remove("hidden")
-      this.iconTarget.classList.add("rotate-180")
-    } else {
-      // Hide the section
-      this.sectionTarget.classList.add("hidden")
-      this.iconTarget.classList.remove("rotate-180")
-    }
-  }
-}