feat: migrate tag management to server actions

- Completed migration of tag management to server actions by creating `actions/tags.ts` for CRUD operations.
- Removed obsolete API routes for tags (`/api/tags`, `/api/tags/[id]`) and updated related components to utilize new server actions.
- Updated `TagForm` and `useTags` hook to handle tag creation, updating, and deletion through server actions, improving performance and simplifying client-side logic.
- Cleaned up `tags-client.ts` by removing unused types and methods, focusing on validation only.
- Marked related TODO items as complete in `TODO.md`.

src/actions/tags.ts

@@ -0,0 +1,101 @@
+'use server';
+
+import { tagsService } from '@/services/tags';
+import { revalidatePath } from 'next/cache';
+import { Tag } from '@/lib/types';
+
+export type ActionResult<T = void> = {
+  success: boolean;
+  data?: T;
+  error?: string;
+};
+
+/**
+ * Créer un nouveau tag
+ */
+export async function createTag(
+  name: string,
+  color: string
+): Promise<ActionResult<Tag>> {
+  try {
+    const tag = await tagsService.createTag({ name, color });
+    
+    // Revalider les pages qui utilisent les tags
+    revalidatePath('/');
+    revalidatePath('/kanban');
+    revalidatePath('/tags');
+    
+    return { success: true, data: tag };
+  } catch (error) {
+    console.error('Error creating tag:', error);
+    return { 
+      success: false, 
+      error: error instanceof Error ? error.message : 'Failed to create tag' 
+    };
+  }
+}
+
+/**
+ * Mettre à jour un tag existant
+ */
+export async function updateTag(
+  tagId: string,
+  data: { name?: string; color?: string; isPinned?: boolean }
+): Promise<ActionResult<Tag>> {
+  try {
+    const tag = await tagsService.updateTag(tagId, data);
+    
+    if (!tag) {
+      return { success: false, error: 'Tag non trouvé' };
+    }
+    
+    // Revalider les pages qui utilisent les tags
+    revalidatePath('/');
+    revalidatePath('/kanban');
+    revalidatePath('/tags');
+    
+    return { success: true, data: tag };
+  } catch (error) {
+    console.error('Error updating tag:', error);
+    return { 
+      success: false, 
+      error: error instanceof Error ? error.message : 'Failed to update tag' 
+    };
+  }
+}
+
+/**
+ * Supprimer un tag
+ */
+export async function deleteTag(tagId: string): Promise<ActionResult> {
+  try {
+    await tagsService.deleteTag(tagId);
+    
+    // Revalider les pages qui utilisent les tags
+    revalidatePath('/');
+    revalidatePath('/kanban');
+    revalidatePath('/tags');
+    
+    return { success: true };
+  } catch (error) {
+    console.error('Error deleting tag:', error);
+    return { 
+      success: false, 
+      error: error instanceof Error ? error.message : 'Failed to delete tag' 
+    };
+  }
+}
+
+/**
+ * Action rapide pour créer un tag depuis un input
+ */
+export async function quickCreateTag(formData: FormData): Promise<ActionResult<Tag>> {
+  const name = formData.get('name') as string;
+  const color = formData.get('color') as string;
+  
+  if (!name?.trim()) {
+    return { success: false, error: 'Tag name is required' };
+  }
+  
+  return createTag(name.trim(), color || '#3B82F6');
+}