perf: load single order group by id in detail view instead of all 430 groups

- add fetchOrderGroupById (single .eq(id).single() query)
- useOrderGroups gains groupId mode: fetches one group, not full 2.6MB list
- GroupDetailPage passes groupId — fixes 30-40s card open on slow connections

src/hooks/useOrderGroups.js

@@ -1,5 +1,5 @@
 import React from "react";
-import { assignDriverToOrderGroup, fetchOrderGroups, saveShipmentData, updateDeliveryStatus, updateOrderGroupDeliveryChoice } from "../services/supabase/orderGroupRepository";
+import { assignDriverToOrderGroup, fetchOrderGroupById, fetchOrderGroups, saveShipmentData, updateDeliveryStatus, updateOrderGroupDeliveryChoice } from "../services/supabase/orderGroupRepository";
 import {
   buildOrderGroupBuckets,
   filterOrderGroups,
@@ -9,7 +9,7 @@ import {
 } from "../services/orderGroupViews";
 import { getErrorMessage } from "../utils/deliveryUtils";
 
-export const useOrderGroups = ({ enabled = true, details = false } = {}) => {
+export const useOrderGroups = ({ enabled = true, details = false, groupId = null } = {}) => {
   const [orderGroups, setOrderGroups] = React.useState(() => []);
   const FILTERS_STORAGE_KEY = "supersam_order_filters";
   const [filters, setFilters] = React.useState(() => {
@@ -41,6 +41,24 @@ export const useOrderGroups = ({ enabled = true, details = false } = {}) => {
 
     if (!enabled) { setOrderGroups([]); setIsLoading(false); return; }
 
+    // Single-group mode: load only the requested group (avoids pulling all
+    // 430 groups with their full source_orders JSON — 2.6MB — for a detail view).
+    if (groupId) {
+      const singleResult = await fetchOrderGroupById(groupId);
+      if (!singleResult) {
+        return;
+      }
+      if (singleResult.error) {
+        setLoadError(singleResult.error?.message || "Не удалось загрузить группу доставки");
+        setOrderGroups([]);
+        setIsLoading(false);
+        return;
+      }
+      setOrderGroups(singleResult.data ? [singleResult.data] : []);
+      setIsLoading(false);
+      return;
+    }
+
     const groupsResult = await fetchOrderGroups({ details });
 
     if (!groupsResult) {
@@ -56,7 +74,7 @@ export const useOrderGroups = ({ enabled = true, details = false } = {}) => {
 
     setOrderGroups(groupsResult.data || []);
     setIsLoading(false);
-  }, [enabled, details]);
+  }, [enabled, details, groupId]);
 
   // Initial load
   React.useEffect(() => {

src/pages/GroupDetailPage.jsx

@@ -38,7 +38,7 @@ export const GroupDetailPage = () => {
     saveShipmentData,
     isLoading,
     refetch,
-  } = useOrderGroups({ details: true });
+  } = useOrderGroups({ details: true, groupId });
 
   // ── Drivers ────────────────────────────────────────────────────────────────
   const [drivers, setDrivers] = React.useState([]);

src/services/supabase/orderGroupRepository.js

@@ -594,3 +594,31 @@ export const fetchOrderGroups = async ({ details = true } = {}) => {
     }).filter(Boolean);
   }, "Ошибка загрузки групп доставки");
 };
+
+export const fetchOrderGroupById = async (orderGroupId) => {
+  return safeSupabaseCall(async () => {
+    const client = requireSupabase();
+    const { data, error } = await client
+      .from("order_groups")
+      .select(ORDER_GROUP_SELECT_FIELDS)
+      .eq("id", orderGroupId)
+      .single();
+
+    if (error) {
+      throw error;
+    }
+
+    const group = mapOrderGroupRowToDeliveryGroup(data);
+    if (group && group.assignedDriverId && !group.assignedDriverName) {
+      const { data: drivers, error: driversError } = await client.rpc("get_drivers");
+      if (!driversError && drivers) {
+        const driver = drivers.find((d) => d.id === group.assignedDriverId);
+        if (driver) {
+          group.assignedDriverName = driver.name || driver.email;
+        }
+      }
+    }
+
+    return group;
+  }, "Ошибка загрузки группы доставки");
+};