feat: add deals, tasks, and organizations pages with CRUD functionality

- Implemented DealsPage with deal creation, updating, and filtering features.
- Added OrganizationsPage to manage and switch between organizations.
- Created TasksPage for task management, including task creation and filtering.
- Updated router to include new pages for navigation.

frontend/src/features/contacts/api.ts

@@ -0,0 +1,35 @@
+import { apiClient } from '@/lib/api-client'
+import type { Contact } from '@/types/crm'
+
+export interface ContactFilters {
+  page?: number
+  pageSize?: number
+  search?: string
+  ownerId?: number
+}
+
+export interface ContactPayload {
+  name: string
+  email?: string | null
+  phone?: string | null
+  owner_id?: number | null
+}
+
+export type ContactUpdatePayload = Partial<Omit<ContactPayload, 'owner_id'>>
+
+const mapFilters = (filters?: ContactFilters) => ({
+  page: filters?.page,
+  page_size: filters?.pageSize,
+  search: filters?.search,
+  owner_id: filters?.ownerId,
+})
+
+export const listContacts = (filters?: ContactFilters) =>
+  apiClient.get<Contact[]>('/contacts/', { params: mapFilters(filters) })
+
+export const createContact = (payload: ContactPayload) => apiClient.post<Contact, ContactPayload>('/contacts/', payload)
+
+export const updateContact = (contactId: number, payload: ContactUpdatePayload) =>
+  apiClient.patch<Contact, ContactUpdatePayload>(`/contacts/${contactId}`, payload)
+
+export const deleteContact = (contactId: number) => apiClient.delete<void>(`/contacts/${contactId}`)