feat: Refactor event equipment management with advanced selection and conflict detection

This commit introduces a complete overhaul of how equipment is assigned to events, focusing on an enhanced user experience, advanced selection capabilities, and robust conflict detection.

**Key Features & Enhancements:**

-   **Advanced Equipment Selection UI (`EquipmentSelectionDialog`):**
    -   New full-screen dialog to select equipment and containers ("boîtes") for an event.
    -   Hierarchical view showing containers and a flat list of all individual equipment.
    -   Real-time search and filtering by equipment category.
    -   Side panel summarizing the current selection and providing recommendations for containers based on selected equipment.
    -   Supports quantity selection for consumables and cables.

-   **Conflict Detection & Management (`EventAvailabilityService`):**
    -   A new service (`EventAvailabilityService`) checks for equipment availability against other events based on the selected date range.
    -   The selection dialog visually highlights equipment and containers with scheduling conflicts (e.g., already used, partially unavailable).
    -   A dedicated conflict resolution dialog (`EquipmentConflictDialog`) appears if conflicting items are selected, allowing the user to either remove them or force the assignment.

-   **Integrated Event Form (`EventAssignedEquipmentSection`):**
    -   The event creation/editing form now includes a new section for managing assigned equipment.
    -   It clearly displays assigned containers and standalone equipment, showing the composition of each container.
    -   Integrates the new selection dialog, ensuring all assignments are checked for conflicts before being saved.

-   **Event Preparation & Return Workflow (`EventPreparationPage`):**
    -   New page (`EventPreparationPage`) for managing the check-out (preparation) and check-in (return) of equipment for an event.
    -   Provides a checklist of all assigned equipment.
    -   Users can validate each item, with options to "validate all" or finalize with missing items.
    -   Includes a dialog (`MissingEquipmentDialog`) to handle discrepancies.
    -   Supports tracking returned quantities for consumables.

**Data Model and Other Changes:**

-   The `EventModel` now includes `assignedContainers` to explicitly link containers to an event.
-   `EquipmentAssociatedEventsSection` on the equipment detail page is now functional, displaying current, upcoming, and past events for that item.
-   Added deployment and versioning scripts (`scripts/deploy.js`, `scripts/increment_version.js`, `scripts/toggle_env.js`) to automate the release process.
-   Introduced an application version display in the main drawer (`AppVersion`).

em2rp/scripts/toggle_env.js

@@ -0,0 +1,87 @@
+#!/usr/bin/env node
+
+/**
+ * Script pour basculer entre mode développement et production
+ */
+
+const fs = require('fs');
+const path = require('path');
+
+const ENV_FILE = path.join(__dirname, '../lib/config/env.dart');
+const ENV_DEV_FILE = path.join(__dirname, '../lib/config/env.dev.dart');
+
+const PROD_CONFIG = `class Env {
+  static const bool isDevelopment = false;
+
+  // Configuration de l'auto-login en développement
+  static const String devAdminEmail = '';
+  static const String devAdminPassword = '';
+
+  // URLs et endpoints
+  static const String baseUrl = 'https://em2rp-951dc.firebaseapp.com';
+
+  // Configuration Firebase
+  static const String firebaseProjectId = 'em2rp-951dc';
+
+  // Autres configurations
+  static const int apiTimeout = 30000; // 30 secondes
+}
+`;
+
+function setProductionMode() {
+  try {
+    // Sauvegarder la config actuelle dans env.dev.dart si elle n'existe pas
+    if (!fs.existsSync(ENV_DEV_FILE) && fs.existsSync(ENV_FILE)) {
+      const currentContent = fs.readFileSync(ENV_FILE, 'utf8');
+      if (currentContent.includes('isDevelopment = true')) {
+        fs.writeFileSync(ENV_DEV_FILE, currentContent, 'utf8');
+        console.log('✅ Configuration de développement sauvegardée dans env.dev.dart');
+      }
+    }
+
+    // Écrire la configuration de production
+    fs.writeFileSync(ENV_FILE, PROD_CONFIG, 'utf8');
+    console.log('✅ Mode PRODUCTION activé (isDevelopment = false, credentials masqués)');
+    return true;
+  } catch (error) {
+    console.error('❌ Erreur lors du basculement en mode production:', error.message);
+    return false;
+  }
+}
+
+function setDevelopmentMode() {
+  try {
+    if (!fs.existsSync(ENV_DEV_FILE)) {
+      console.error('❌ Fichier env.dev.dart introuvable. Créez-le d\'abord avec vos credentials.');
+      return false;
+    }
+
+    const devContent = fs.readFileSync(ENV_DEV_FILE, 'utf8');
+    fs.writeFileSync(ENV_FILE, devContent, 'utf8');
+    console.log('✅ Mode DÉVELOPPEMENT activé (isDevelopment = true)');
+    return true;
+  } catch (error) {
+    console.error('❌ Erreur lors du basculement en mode développement:', error.message);
+    return false;
+  }
+}
+
+// Exécuter si appelé directement
+if (require.main === module) {
+  const args = process.argv.slice(2);
+  const mode = args[0];
+
+  if (mode === 'prod' || mode === 'production') {
+    process.exit(setProductionMode() ? 0 : 1);
+  } else if (mode === 'dev' || mode === 'development') {
+    process.exit(setDevelopmentMode() ? 0 : 1);
+  } else {
+    console.log('Usage: node toggle_env.js [prod|dev]');
+    console.log('  prod : Bascule en mode production (isDevelopment = false, sans credentials)');
+    console.log('  dev  : Bascule en mode développement (isDevelopment = true, avec credentials)');
+    process.exit(1);
+  }
+}
+
+module.exports = { setProductionMode, setDevelopmentMode };
+