feat: RefBoard v0.4.0 — collaborative reference board with layers, groups & polished UI

Full-featured PureRef-style collaborative canvas for game dev teams:
- Layer panel with visibility, lock, drag reorder, group/ungroup (Ctrl+G/Shift+G)
- Arrangement tools (grid, row, column) via right-click context menu
- Copy to system clipboard (Ctrl+C writes PNG for external paste in Paint etc.)
- Number shortcuts (1-5) for tool selection with visible shortcut badges
- Premium dark UI across all pages (Login, Collections, Boards, Editor)
- Socket.IO rooms for cursors, transforms, and presence notifications
- MinIO image storage with backend proxy, drag/drop and paste upload

frontend/src/api.ts

@@ -0,0 +1,114 @@
+import axios from 'axios';
+import { getToken, removeToken } from './auth';
+
+const api = axios.create({
+  baseURL: window.location.origin,
+});
+
+api.interceptors.request.use((config) => {
+  const token = getToken();
+  if (token) {
+    config.headers.Authorization = `Bearer ${token}`;
+  }
+  return config;
+});
+
+api.interceptors.response.use(
+  (response) => response,
+  (error) => {
+    if (error.response?.status === 401) {
+      removeToken();
+      if (window.location.pathname !== '/login') {
+        window.location.href = '/login';
+      }
+    }
+    return Promise.reject(error);
+  }
+);
+
+// Auth
+export function login(email: string, password: string) {
+  return api.post('/api/auth/login', { email, password });
+}
+
+export function register(email: string, username: string, password: string, displayName: string) {
+  return api.post('/api/auth/register', { email, username, password, display_name: displayName });
+}
+
+export function getMe() {
+  return api.get('/api/auth/me');
+}
+
+// Collections
+export function getCollections(search?: string) {
+  const params: Record<string, string> = {};
+  if (search) params.search = search;
+  return api.get('/api/collections', { params });
+}
+
+export function createCollection(name: string, description?: string) {
+  return api.post('/api/collections', { name, description });
+}
+
+export function getCollectionDetail(collectionId: string) {
+  return api.get(`/api/collections/${collectionId}`);
+}
+
+export function deleteCollection(collectionId: string) {
+  return api.delete(`/api/collections/${collectionId}`);
+}
+
+export function getCollectionShareInfo(collectionId: string) {
+  return api.get(`/api/collections/${collectionId}/share`);
+}
+
+export function shareCollection(collectionId: string, isPublic: boolean) {
+  return api.post(`/api/collections/${collectionId}/share`, { is_public: isPublic });
+}
+
+export function addCollectionMember(collectionId: string, email: string, role: string = 'editor') {
+  return api.post(`/api/collections/${collectionId}/members`, { email, role });
+}
+
+export function removeCollectionMember(collectionId: string, userId: string) {
+  return api.delete(`/api/collections/${collectionId}/members/${userId}`);
+}
+
+export function searchUsers(query: string) {
+  return api.get('/api/users/search', { params: { q: query } });
+}
+
+export function getCollectionByShareToken(shareToken: string) {
+  return api.get(`/api/c/${shareToken}`);
+}
+
+// Boards
+export function createBoard(collectionId: string, name: string, description?: string) {
+  return api.post('/api/boards', { collection_id: collectionId, name, description });
+}
+
+export function getBoard(boardId: string) {
+  return api.get(`/api/boards/${boardId}`);
+}
+
+export function deleteBoard(boardId: string) {
+  return api.delete(`/api/boards/${boardId}`);
+}
+
+export function saveCanvas(boardId: string, canvasState: string) {
+  return api.post(`/api/boards/${boardId}/save`, { canvas_state: canvasState });
+}
+
+export function uploadImage(boardId: string, file: File) {
+  const formData = new FormData();
+  formData.append('image', file);
+  return api.post(`/api/upload/boards/${boardId}/images`, formData, {
+    headers: { 'Content-Type': 'multipart/form-data' },
+  });
+}
+
+export function uploadImageFromUrl(boardId: string, url: string) {
+  return api.post(`/api/upload/boards/${boardId}/images/from-url`, { url });
+}
+
+export default api;