Implement Phase 5: reconciliation, SignalR notifications, payees, splits & plugins

Add full frontend UI for five backend features: bank reconciliation (3-step
stepper workflow), payee management (CRUD with alias chips), transaction splits
(expandable rows + split editor), plugins (card grid), and real-time SignalR
notifications (bell dropdown with badge). Fix backend PayeeResponse to expose
alias IDs for deletion.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/services/payees.ts

@@ -0,0 +1,12 @@
+import api from './api'
+import type { Payee, CreatePayeeRequest, UpdatePayeeRequest } from '@/types'
+
+export const payeesApi = {
+  getAll: () => api.get<Payee[]>('/payees'),
+  getById: (id: string) => api.get<Payee>(`/payees/${id}`),
+  create: (data: CreatePayeeRequest) => api.post<Payee>('/payees', data),
+  update: (id: string, data: UpdatePayeeRequest) => api.put<Payee>(`/payees/${id}`, data),
+  delete: (id: string) => api.delete(`/payees/${id}`),
+  addAlias: (payeeId: string, alias: string) => api.post(`/payees/${payeeId}/aliases`, { alias }),
+  removeAlias: (payeeId: string, aliasId: string) => api.delete(`/payees/${payeeId}/aliases/${aliasId}`),
+}

frontend/src/services/plugins.ts

@@ -0,0 +1,6 @@
+import api from './api'
+import type { Plugin } from '@/types'
+
+export const pluginsApi = {
+  getAll: () => api.get<Plugin[]>('/plugins'),
+}

frontend/src/services/reconciliation.ts

@@ -0,0 +1,11 @@
+import api from './api'
+import type { ReconciliationResponse, StartReconciliationRequest } from '@/types'
+
+export const reconciliationApi = {
+  start: (accountId: string, data: StartReconciliationRequest) =>
+    api.post<ReconciliationResponse>(`/reconciliation/${accountId}/start`, data),
+  complete: (accountId: string, reconciliationId: string) =>
+    api.post(`/reconciliation/${accountId}/complete`, null, { params: { reconciliationId } }),
+  cancel: (accountId: string, reconciliationId: string) =>
+    api.post(`/reconciliation/${accountId}/cancel`, null, { params: { reconciliationId } }),
+}