feat: Implement comprehensive event management system for promoters

This commit adds a complete event management interface allowing promoters to 
create, edit, and manage their events with full CRUD operations.

## Backend Features
- New Promoter::EventsController with full CRUD operations
- Event state management (draft, published, canceled, sold_out)
- User authorization system with can_manage_events? method
- Proper scoping to ensure users only see their own events

## Frontend Features  
- Modern responsive UI with Tailwind CSS styling
- Event listing with status indicators and quick actions
- Comprehensive event creation and editing forms
- Detailed event show page with metrics and management options
- Integration with main dashboard via promoter action buttons

## JavaScript Improvements
- Refactored inline JavaScript to dedicated Stimulus controller
- Auto-slug generation from event names with proper sanitization
- Improved code organization following Rails conventions

## Routes & Navigation
- Namespaced promoter routes under /promoter/
- RESTful endpoints with state management actions
- Proper breadcrumb navigation and user flow

## Files Added/Modified
- app/controllers/promoter/events_controller.rb (new)
- app/javascript/controllers/event_form_controller.js (new) 
- app/views/promoter/events/*.html.erb (4 new view files)
- app/models/user.rb (added authorization methods)
- app/views/pages/dashboard.html.erb (added promoter buttons)
- config/routes.rb (added promoter namespace)
- app/javascript/controllers/index.js (registered new controller)

🎯 Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

app/javascript/controllers/event_form_controller.js

@@ -0,0 +1,28 @@
+import { Controller } from "@hotwired/stimulus"
+
+// Event form controller for handling form interactions
+// Handles auto-slug generation from event names
+export default class extends Controller {
+  static targets = ["name", "slug"]
+
+  connect() {
+    console.log("Event form controller connected")
+  }
+
+  // Auto-generate slug from name input
+  generateSlug() {
+    // Only auto-generate if slug field is empty
+    if (this.slugTarget.value === "") {
+      const slug = this.nameTarget.value
+        .toLowerCase()
+        .normalize("NFD")
+        .replace(/[\u0300-\u036f]/g, "") // Remove accents
+        .replace(/[^a-z0-9\s-]/g, "") // Remove special chars
+        .replace(/\s+/g, "-") // Replace spaces with dashes
+        .replace(/-+/g, "-") // Remove duplicate dashes
+        .replace(/^-|-$/g, "") // Remove leading/trailing dashes
+      
+      this.slugTarget.value = slug
+    }
+  }
+}