feat(web): API client methods for peering subscriptions and notifications

- Drops the web-local ApprovalRequest interface in favor of the
  canonical shared type (Task 2 already established this; Task 10
  reconciles the consumer side).
- Adds five new federation methods wrapping the REST endpoints
  added in Tasks 8 and 9: peeringSubscriptions (GET), cancelPeering
  Subscription (DELETE), peeringNotifications (GET +/- unreadOnly
  filter), markPeeringNotificationRead (POST :id/read), markAll
  PeeringNotificationsRead (POST read-all).

packages/web/src/api/client.ts

@@ -53,9 +53,12 @@ import type {
   FederationIdentityDeleteRequest,
   FederationIdentityDeleteResponse,
   FederationPeer,
+  ApprovalRequest,
+  PeeringSubscription,
+  PeeringNotification,
 } from '@backspace/shared';
 
-export type { FederationPeer };
+export type { FederationPeer, ApprovalRequest, PeeringSubscription, PeeringNotification };
 
 export class RateLimitError extends Error {
   readonly retryAfter: number;
@@ -66,14 +69,6 @@ export class RateLimitError extends Error {
   }
 }
 
-export interface ApprovalRequest {
-  id: string;
-  origin: string;
-  instanceName: string | null;
-  requestedAt: number;
-  expiresAt: number;
-}
-
 export class BackspaceApiClient {
   readonly auth: {
     register: (data: RegisterRequest) => Promise<AuthResponse>;
@@ -230,6 +225,11 @@ export class BackspaceApiClient {
     approvalRequests: () => Promise<{ requests: ApprovalRequest[] }>;
     approveRequest: (id: string) => Promise<{ success: boolean; peer?: FederationPeer }>;
     denyRequest: (id: string) => Promise<{ success: boolean }>;
+    peeringSubscriptions: () => Promise<{ subscriptions: PeeringSubscription[] }>;
+    cancelPeeringSubscription: (id: string) => Promise<{ success: boolean }>;
+    peeringNotifications: (unreadOnly?: boolean) => Promise<{ notifications: PeeringNotification[] }>;
+    markPeeringNotificationRead: (id: string) => Promise<{ success: boolean }>;
+    markAllPeeringNotificationsRead: () => Promise<{ success: boolean; count: number }>;
   };
 
   readonly admin: {
@@ -697,6 +697,27 @@ export class BackspaceApiClient {
         request<{ success: boolean }>(
           'POST', `/federation/approval-requests/${id}/deny`
         ),
+      peeringSubscriptions: () =>
+        request<{ subscriptions: PeeringSubscription[] }>(
+          'GET', '/federation/peering-subscriptions'
+        ),
+      cancelPeeringSubscription: (id: string) =>
+        request<{ success: boolean }>(
+          'DELETE', `/federation/peering-subscriptions/${id}`
+        ),
+      peeringNotifications: (unreadOnly = false) =>
+        request<{ notifications: PeeringNotification[] }>(
+          'GET',
+          `/federation/peering-notifications${unreadOnly ? '?unread=1' : ''}`,
+        ),
+      markPeeringNotificationRead: (id: string) =>
+        request<{ success: boolean }>(
+          'POST', `/federation/peering-notifications/${id}/read`
+        ),
+      markAllPeeringNotificationsRead: () =>
+        request<{ success: boolean; count: number }>(
+          'POST', '/federation/peering-notifications/read-all'
+        ),
     };
 
     this.admin = {