feat: implement getWeekBounds function for calculating ISO week boundaries and integrate it into weather session sharing logic

src/services/weather.ts

@@ -1,5 +1,6 @@
 import { prisma } from '@/services/database';
 import { getTeamMemberIdsForAdminTeams } from '@/services/teams';
+import { getWeekBounds } from '@/lib/date-utils';
 import type { ShareRole } from '@prisma/client';
 
 // ============================================
@@ -301,21 +302,43 @@ export async function shareWeatherSessionToTeam(
     throw new Error('Session not found or not owned');
   }
 
-  // Get team members
+  // Max 1 météo par équipe par semaine
   const teamMembers = await prisma.teamMember.findMany({
+    where: { teamId },
+    select: { userId: true },
+  });
+  const teamMemberIds = teamMembers.map((tm) => tm.userId);
+  if (teamMemberIds.length > 0) {
+    const { start: weekStart, end: weekEnd } = getWeekBounds(session.date);
+    const existingCount = await prisma.weatherSession.count({
+      where: {
+        id: { not: sessionId },
+        date: { gte: weekStart, lte: weekEnd },
+        shares: {
+          some: { userId: { in: teamMemberIds } },
+        },
+      },
+    });
+    if (existingCount > 0) {
+      throw new Error("Cette équipe a déjà une météo pour cette semaine");
+    }
+  }
+
+  // Get team members (full)
+  const teamMembersFull = await prisma.teamMember.findMany({
     where: { teamId },
     include: {
       user: { select: { id: true, name: true, email: true } },
     },
   });
 
-  if (teamMembers.length === 0) {
+  if (teamMembersFull.length === 0) {
     throw new Error('Team has no members');
   }
 
   // Share with all team members (except owner)
   const shares = await Promise.all(
-    teamMembers
+    teamMembersFull
       .filter((tm) => tm.userId !== ownerId) // Don't share with yourself
       .map((tm) =>
         prisma.weatherSessionShare.upsert({