fix: Tasks API - map assigneeId query param to assignedToId schema field

Root cause: Prisma schema uses 'assignedToId' but getTasks was passing
'assigneeId' directly to the where clause, causing PrismaClientValidationError

backend/src/controllers/tasks.controller.ts

@@ -8,7 +8,7 @@ export const getTasks = async (request: FastifyRequest, reply: FastifyReply) =>
         const tasks = await request.server.prisma.task.findMany({
             where: {
                 ...(status && { status }),
-                ...(assigneeId && { assigneeId }),
+                ...(assigneeId && { assignedToId: assigneeId }),
                 ...(roomId && { roomId }),
                 ...(batchId && { batchId }),
                 ...(startDate && endDate && {