refactor: rename module to pipely and migrate web UI to MUI

- Rename Go module from onixbyte.com/message-converter-manifest to onixbyte.com/pipely
- Replace shadcn UI with Material UI components across all pages
- Add axios-based API client in shared/web-client with credentials management
- Organise API calls into feature modules: auth, devices, deployments, artefacts, users
- Add .env.example with VITE_API_BASE_URL pointing to pipely.onixbyte.com
- Fix deprecated FormEvent → MouseEvent in dialog submit handlers

web/src/api/users/index.ts

@@ -0,0 +1,59 @@
+import WebClient from "@/shared/web-client"
+
+export interface User {
+  id: string
+  username: string
+  role: "admin" | "user"
+  createdAt: string
+  updatedAt: string
+}
+
+export interface CreateUserRequest {
+  username: string
+  password: string
+  role: "admin" | "user"
+}
+
+export interface UpdateUserRequest {
+  username?: string
+  password?: string
+  role?: "admin" | "user"
+}
+
+export interface UsersResponse {
+  data: User[]
+  total: number
+  page: number
+  pageSize: number
+}
+
+export interface UsersQuery {
+  page?: number
+  pageSize?: number
+}
+
+export async function getUsers(query?: UsersQuery): Promise<UsersResponse> {
+  const params = new URLSearchParams()
+  if (query?.page) params.append("page", query.page.toString())
+  if (query?.pageSize) params.append("pageSize", query.pageSize.toString())
+
+  const queryString = params.toString()
+  const { data } = await WebClient.get<UsersResponse>(
+    `/users${queryString ? `?${queryString}` : ""}`
+  )
+  return data
+}
+
+export async function createUser(request: CreateUserRequest): Promise<User> {
+  const { data } = await WebClient.post<User>("/users", request)
+  return data
+}
+
+export async function updateUser(id: string, request: UpdateUserRequest): Promise<User> {
+  const { data } = await WebClient.put<User>(`/users/${id}`, request)
+  return data
+}
+
+export async function deleteUser(id: string): Promise<void> {
+  await WebClient.delete<void>(`/users/${id}`)
+}