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/views/pages/dashboard.html.erb

@@ -1,7 +1,23 @@
 <div class="container mx-auto px-4 sm:px-6 lg:px-8 py-8">
   <!-- Hero section with metrics -->
   <div class="mb-8">
-    <h1 class="text-3xl font-bold text-slate-900 dark:text-slate-100 mb-6">Tableau de bord</h1>
+    <div class="flex items-center justify-between mb-6">
+      <h1 class="text-3xl font-bold text-slate-900 dark:text-slate-100">Tableau de bord</h1>
+      
+      <!-- Promoter Actions -->
+      <% if current_user.promoter? %>
+        <div class="flex items-center space-x-3">
+          <%= link_to promoter_events_path, class: "inline-flex items-center px-4 py-2 bg-purple-600 text-white font-medium rounded-lg hover:bg-purple-700 transition-colors duration-200" do %>
+            <i data-lucide="calendar-plus" class="w-4 h-4 mr-2"></i>
+            Mes événements
+          <% end %>
+          <%= link_to new_promoter_event_path, class: "inline-flex items-center px-4 py-2 bg-black text-white font-medium rounded-lg hover:bg-gray-800 transition-colors duration-200" do %>
+            <i data-lucide="plus" class="w-4 h-4 mr-2"></i>
+            Créer un événement
+          <% end %>
+        </div>
+      <% end %>
+    </div>
     <div class="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-4 gap-6">
 
       <%= render partial: 'components/metric_card', locals: { title: "Mes réservations", value: @booked_events, classes: "from-green-100 to-emerald-100" } %>