feat: inversion relation User→Projects, les projets pointent vers les utilisateurs

Le champ `users` est désormais sur le blueprint projet. Les blueprints
pochet/client perdent leur champ `projects`. La logique PHP (user-projects,
managers, controller, template, mark-all-read) lit project.users au lieu
de user.projects. Script de migration inclus.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

public/site/blueprints/pages/project.yml

@@ -85,6 +85,10 @@ tabs:
               query: page.logo.toFile
             layout: cardlets
             required: true
+          users:
+            label: Utilisateurs assignés
+            type: users
+            multiple: true
 
       - width: 2/3
         sections:

public/site/blueprints/users/client.yml

@@ -36,7 +36,7 @@ sections:
           fr: Projet(s) en cours
           en: Current project(s)
         link: https://designtopack.morphozbygroupepochet.com/
-        value: "{{ user.projects.toPages.count }}"
+        value: "{{ user.currentProjects.count }}"
         icon: folder
   content:
     label: ' '
@@ -52,8 +52,3 @@ sections:
         layout: cardlets
         required: true
         width: 1/2
-      projects:
-        label: Projets
-        type: pages
-        query: page('projects').children
-        width: 1/2

public/site/blueprints/users/pochet.yml

@@ -14,11 +14,6 @@ fields:
       - Sales Manager
     default: Project Panager
     width: 1/4
-  projects:
-    label: Projets
-    type: pages
-    query: page('projects').children
-    width: 3/4
   hiddenProjects:
     label: Projets masqués
     type: pages