feat: enhance HomePage with tag metrics and analytics integration

- Added TagAnalyticsService to fetch tag distribution metrics for the HomePage.
- Updated HomePageClient and ProductivityAnalytics components to utilize new tag metrics.
- Refactored TagsClient to use utility functions for color validation and generation.
- Simplified TagForm to use centralized tag colors from TAG_COLORS.

src/clients/tags-client.ts

@@ -1,5 +1,6 @@
 import { HttpClient } from './base/http-client';
 import { Tag } from '@/lib/types';
+import { generateRandomTagColor, isValidTagColor } from '@/lib/tag-colors';
 
 // Types pour les requêtes (now only used for validation - CRUD operations moved to server actions)
 
@@ -85,27 +86,14 @@ export class TagsClient extends HttpClient {
    * Valide le format d'une couleur hexadécimale
    */
   static isValidColor(color: string): boolean {
-    return /^#[0-9A-F]{6}$/i.test(color);
+    return isValidTagColor(color);
   }
 
   /**
    * Génère une couleur aléatoire pour un nouveau tag
    */
   static generateRandomColor(): string {
-    const colors = [
-      '#3B82F6', // Blue
-      '#EF4444', // Red
-      '#10B981', // Green
-      '#F59E0B', // Yellow
-      '#8B5CF6', // Purple
-      '#EC4899', // Pink
-      '#06B6D4', // Cyan
-      '#84CC16', // Lime
-      '#F97316', // Orange
-      '#6366F1', // Indigo
-    ];
-    
-    return colors[Math.floor(Math.random() * colors.length)];
+    return generateRandomTagColor();
   }
 
   /**