feat(psa): add Integrations page with connection management UI

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/api/index.ts

@@ -22,3 +22,4 @@ export { assistantChatApi } from './assistantChat'
 export { flowTransferApi } from './flowTransfer'
 export { kbAcceleratorApi } from './kbAccelerator'
 export { scriptsApi } from './scripts'
+export { integrationsApi } from './integrations'

frontend/src/api/integrations.ts

@@ -0,0 +1,15 @@
+import { apiClient } from './client'
+import type { PsaConnectionResponse, PsaConnectionCreate, PsaConnectionUpdate, PsaConnectionTestResponse } from '@/types'
+
+export const integrationsApi = {
+  getConnection: () =>
+    apiClient.get<PsaConnectionResponse | null>('/integrations/psa/connections').then(r => r.data),
+  createConnection: (data: PsaConnectionCreate) =>
+    apiClient.post<PsaConnectionResponse>('/integrations/psa/connections', data).then(r => r.data),
+  updateConnection: (id: string, data: PsaConnectionUpdate) =>
+    apiClient.put<PsaConnectionResponse>(`/integrations/psa/connections/${id}`, data).then(r => r.data),
+  deleteConnection: (id: string) =>
+    apiClient.delete(`/integrations/psa/connections/${id}`),
+  testConnection: (id: string) =>
+    apiClient.post<PsaConnectionTestResponse>(`/integrations/psa/connections/${id}/test`).then(r => r.data),
+}