feat: add pinned tag functionality and UI enhancements

- Introduced `isPinned` property to the `Tag` model for marking main objectives.
- Updated `TagForm` to include a checkbox for setting tags as pinned, enhancing user interaction.
- Enhanced `KanbanBoardContainer` to display pinned tasks in a dedicated `ObjectivesBoard`, improving task visibility.
- Modified `KanbanFilters` to support filtering by pinned tags, streamlining task management.
- Adjusted `TasksContext` to separate pinned tasks from regular tasks for better organization.

services/tags.ts

@@ -24,6 +24,7 @@ export const tagsService = {
       id: tag.id,
       name: tag.name,
       color: tag.color,
+      isPinned: tag.isPinned,
       usage: tag._count.taskTags
     }));
   },
@@ -41,7 +42,8 @@ export const tagsService = {
     return {
       id: tag.id,
       name: tag.name,
-      color: tag.color
+      color: tag.color,
+      isPinned: tag.isPinned
     };
   },
 
@@ -62,14 +64,15 @@ export const tagsService = {
     return {
       id: tag.id,
       name: tag.name,
-      color: tag.color
+      color: tag.color,
+      isPinned: tag.isPinned
     };
   },
 
   /**
    * Crée un nouveau tag
    */
-  async createTag(data: { name: string; color: string }): Promise<Tag> {
+  async createTag(data: { name: string; color: string; isPinned?: boolean }): Promise<Tag> {
     // Vérifier si le tag existe déjà
     const existing = await this.getTagByName(data.name);
     if (existing) {
@@ -79,21 +82,23 @@ export const tagsService = {
     const tag = await prisma.tag.create({
       data: {
         name: data.name.trim(),
-        color: data.color
+        color: data.color,
+        isPinned: data.isPinned || false
       }
     });
 
     return {
       id: tag.id,
       name: tag.name,
-      color: tag.color
+      color: tag.color,
+      isPinned: tag.isPinned
     };
   },
 
   /**
    * Met à jour un tag
    */
-  async updateTag(id: string, data: { name?: string; color?: string }): Promise<Tag | null> {
+  async updateTag(id: string, data: { name?: string; color?: string; isPinned?: boolean }): Promise<Tag | null> {
     // Vérifier que le tag existe
     const existing = await this.getTagById(id);
     if (!existing) {
@@ -115,6 +120,9 @@ export const tagsService = {
     if (data.color !== undefined) {
       updateData.color = data.color;
     }
+    if (data.isPinned !== undefined) {
+      updateData.isPinned = data.isPinned;
+    }
 
     if (Object.keys(updateData).length === 0) {
       return existing;
@@ -128,7 +136,8 @@ export const tagsService = {
     return {
       id: tag.id,
       name: tag.name,
-      color: tag.color
+      color: tag.color,
+      isPinned: tag.isPinned
     };
   },
 
@@ -197,7 +206,8 @@ export const tagsService = {
     return tags.map(tag => ({
       id: tag.id,
       name: tag.name,
-      color: tag.color
+      color: tag.color,
+      isPinned: tag.isPinned
     }));
   },