feat(webhook): Phase 4 — admin-ui /webhooks page

Routes:
- /webhooks (layout) → /webhooks/index (list) + /webhooks/$id (detail)
- nav link добавлен в __root.tsx между Outbox и Language switch

List page (webhooks.index.tsx):
- Table: name | URL | scope filter (colored dots) | dictionaries | status
- ScopeChips reuse SCOPE_DOT из lib/scope-style.ts (consistency с
  dictionaries scope coloring)
- Create dialog: name, URL, scope filter (MultiSelect), dictionary &
  event type (CSV inputs), description. Client-side validation
  (URL scheme, name required) дублирует server-side @Pattern.
- Secret reveal modal после create: warning + plaintext + copy button.
  Single-time view — после закрытия secret не получить, только rotate.

Detail page (webhooks.$id.tsx):
- Subscription metadata grid (URL, status, filters, masked secret,
  createdBy + timestamp)
- Action buttons: rotate-secret + delete (с confirmation)
- Delivery history table: outboxEventId | status badge (delivered/
  retrying/pending/dlq) | attempts | last attempt | HTTP code | error
- Pagination 50/page
- Status badges: delivered=success, retrying=warning, pending=neutral,
  dlq=error

API client (queries + mutations):
- 4 queries: subscriptions list, subscription by id, deliveries page,
  DLQ page (last unused в UI пока, но готов для admin DLQ tab)
- 4 mutations: create, update, delete, rotateSecret. Все invalidate
  правильные query keys.

i18n: 50 ключей × 2 локали (ru-RU + en-US) под webhooks.*

ordinis-admin-ui/src/api/mutations.ts

@@ -3,8 +3,10 @@ import {
   apiClient,
   type CreateDictionaryRequest,
   type CreateRecordRequest,
+  type CreateWebhookSubscriptionRequest,
   type DictionaryDetail,
   type RecordResponse,
+  type WebhookSubscription,
 } from './client'
 
 const idempotencyKey = () =>
@@ -96,3 +98,69 @@ export const useCloseRecord = (dictionaryName: string) => {
     },
   })
 }
+
+// === Webhooks (v2) ===
+
+export const useCreateWebhook = () => {
+  const qc = useQueryClient()
+  return useMutation({
+    mutationFn: async (req: CreateWebhookSubscriptionRequest): Promise<WebhookSubscription> => {
+      const { data } = await apiClient.post<WebhookSubscription>(
+        '/admin/webhooks/subscriptions',
+        req,
+      )
+      return data
+    },
+    onSuccess: () => {
+      qc.invalidateQueries({ queryKey: ['webhooks', 'subscriptions'] })
+    },
+  })
+}
+
+export const useUpdateWebhook = () => {
+  const qc = useQueryClient()
+  return useMutation({
+    mutationFn: async (params: {
+      id: string
+      payload: CreateWebhookSubscriptionRequest
+    }): Promise<WebhookSubscription> => {
+      const { data } = await apiClient.put<WebhookSubscription>(
+        `/admin/webhooks/subscriptions/${encodeURIComponent(params.id)}`,
+        params.payload,
+      )
+      return data
+    },
+    onSuccess: (_data, vars) => {
+      qc.invalidateQueries({ queryKey: ['webhooks', 'subscriptions'] })
+      qc.invalidateQueries({ queryKey: ['webhooks', 'subscriptions', vars.id] })
+    },
+  })
+}
+
+export const useDeleteWebhook = () => {
+  const qc = useQueryClient()
+  return useMutation({
+    mutationFn: async (id: string): Promise<void> => {
+      await apiClient.delete(`/admin/webhooks/subscriptions/${encodeURIComponent(id)}`)
+    },
+    onSuccess: () => {
+      qc.invalidateQueries({ queryKey: ['webhooks', 'subscriptions'] })
+    },
+  })
+}
+
+export const useRotateWebhookSecret = () => {
+  const qc = useQueryClient()
+  return useMutation({
+    mutationFn: async (id: string): Promise<WebhookSubscription> => {
+      const { data } = await apiClient.post<WebhookSubscription>(
+        `/admin/webhooks/subscriptions/${encodeURIComponent(id)}/rotate-secret`,
+      )
+      return data
+    },
+    onSuccess: (_data, id) => {
+      qc.invalidateQueries({ queryKey: ['webhooks', 'subscriptions'] })
+      qc.invalidateQueries({ queryKey: ['webhooks', 'subscriptions', id] })
+    },
+  })
+}