feat: add 'Utilisateurs' link to Header component and implement user statistics retrieval in auth service

src/services/auth.ts

@@ -144,3 +144,61 @@ export async function updateUserPassword(
   return { success: true };
 }
 
+export interface UserStats {
+  sessions: number;
+  motivatorSessions: number;
+  sharedSessions: number;
+  sharedMotivatorSessions: number;
+}
+
+export interface UserWithStats {
+  id: string;
+  email: string;
+  name: string | null;
+  createdAt: Date;
+  updatedAt: Date;
+  _count: UserStats;
+}
+
+export async function getAllUsersWithStats(): Promise<UserWithStats[]> {
+  const users = await prisma.user.findMany({
+    select: {
+      id: true,
+      email: true,
+      name: true,
+      createdAt: true,
+      updatedAt: true,
+      _count: {
+        select: {
+          sessions: true,
+          sharedSessions: true,
+        },
+      },
+    },
+    orderBy: { createdAt: 'desc' },
+  });
+
+  // Get motivator sessions count separately (Prisma doesn't have these in User model _count directly)
+  const usersWithMotivators = await Promise.all(
+    users.map(async (user) => {
+      const motivatorCount = await prisma.movingMotivatorsSession.count({
+        where: { userId: user.id },
+      });
+      const sharedMotivatorCount = await prisma.mMSessionShare.count({
+        where: { userId: user.id },
+      });
+
+      return {
+        ...user,
+        _count: {
+          ...user._count,
+          motivatorSessions: motivatorCount,
+          sharedMotivatorSessions: sharedMotivatorCount,
+        },
+      };
+    })
+  );
+
+  return usersWithMotivators;
+}
+