feat(frontend): add React dashboard with TypeScript

Add modern React frontend to replace Streamlit dashboard:
- Vite build system with TypeScript
- Tailwind CSS for styling
- Component structure in src/
- Production Dockerfile with nginx
- Development server on port 5173

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

frontend/src/api/client.ts

@@ -0,0 +1,154 @@
+import axios, { AxiosError, InternalAxiosRequestConfig } from 'axios';
+import type { TokenResponse, User, CompanyAnalysis, BatchAnalysisResult, JobStatus, Analytics } from '../types';
+
+const API_BASE_URL = import.meta.env.VITE_API_URL || '/api';
+
+const api = axios.create({
+  baseURL: API_BASE_URL,
+  headers: {
+    'Content-Type': 'application/json',
+  },
+});
+
+// Token management
+let accessToken: string | null = localStorage.getItem('access_token');
+let refreshToken: string | null = localStorage.getItem('refresh_token');
+
+export const setTokens = (tokens: TokenResponse) => {
+  accessToken = tokens.access_token;
+  refreshToken = tokens.refresh_token;
+  localStorage.setItem('access_token', tokens.access_token);
+  localStorage.setItem('refresh_token', tokens.refresh_token);
+};
+
+export const clearTokens = () => {
+  accessToken = null;
+  refreshToken = null;
+  localStorage.removeItem('access_token');
+  localStorage.removeItem('refresh_token');
+};
+
+export const getAccessToken = () => accessToken;
+
+// Request interceptor to add auth header
+api.interceptors.request.use((config: InternalAxiosRequestConfig) => {
+  if (accessToken) {
+    config.headers.Authorization = `Bearer ${accessToken}`;
+  }
+  return config;
+});
+
+// Response interceptor to handle token refresh
+api.interceptors.response.use(
+  (response) => response,
+  async (error: AxiosError) => {
+    const originalRequest = error.config as InternalAxiosRequestConfig & { _retry?: boolean };
+
+    if (error.response?.status === 401 && !originalRequest._retry && refreshToken) {
+      originalRequest._retry = true;
+
+      try {
+        const response = await axios.post<TokenResponse>(`${API_BASE_URL}/auth/refresh`, {
+          refresh_token: refreshToken,
+        });
+
+        setTokens(response.data);
+        originalRequest.headers.Authorization = `Bearer ${response.data.access_token}`;
+
+        return api(originalRequest);
+      } catch {
+        clearTokens();
+        window.location.href = '/login';
+      }
+    }
+
+    return Promise.reject(error);
+  }
+);
+
+// Auth API
+export const authApi = {
+  register: async (email: string, password: string): Promise<User> => {
+    const response = await api.post<User>('/auth/register', { email, password });
+    return response.data;
+  },
+
+  login: async (email: string, password: string): Promise<TokenResponse> => {
+    const response = await api.post<TokenResponse>('/auth/login', { email, password });
+    setTokens(response.data);
+    return response.data;
+  },
+
+  getMe: async (): Promise<User> => {
+    const response = await api.get<User>('/auth/me');
+    return response.data;
+  },
+
+  logout: () => {
+    clearTokens();
+  },
+};
+
+// Analysis API
+export const analysisApi = {
+  analyzeCompany: async (companyName: string): Promise<CompanyAnalysis> => {
+    const response = await api.get<CompanyAnalysis>(`/analyze/${encodeURIComponent(companyName)}`);
+    return response.data;
+  },
+
+  analyzeBatch: async (companies: string[], maxWorkers = 3): Promise<BatchAnalysisResult> => {
+    const response = await api.post<BatchAnalysisResult>('/analyze/batch', {
+      companies,
+      max_workers: maxWorkers,
+    });
+    return response.data;
+  },
+
+  analyzeBatchAsync: async (companies: string[], maxWorkers = 3): Promise<JobStatus> => {
+    const response = await api.post<JobStatus>('/analyze/batch/async', {
+      companies,
+      max_workers: maxWorkers,
+    });
+    return response.data;
+  },
+
+  getJobStatus: async (jobId: string): Promise<JobStatus> => {
+    const response = await api.get<JobStatus>(`/jobs/${jobId}`);
+    return response.data;
+  },
+
+  listJobs: async (status?: string, limit = 10): Promise<JobStatus[]> => {
+    const params = new URLSearchParams();
+    if (status) params.append('status', status);
+    params.append('limit', limit.toString());
+    const response = await api.get<JobStatus[]>(`/jobs?${params}`);
+    return response.data;
+  },
+};
+
+// Analytics API
+export const analyticsApi = {
+  getAnalytics: async (days = 30): Promise<Analytics> => {
+    const response = await api.get<Analytics>(`/analytics?days=${days}`);
+    return response.data;
+  },
+};
+
+// Admin API
+export const adminApi = {
+  listUsers: async (limit = 100, offset = 0): Promise<User[]> => {
+    const response = await api.get<User[]>(`/admin/users?limit=${limit}&offset=${offset}`);
+    return response.data;
+  },
+
+  updateUserRole: async (userId: number, role: 'admin' | 'user'): Promise<User> => {
+    const response = await api.patch<User>(`/admin/users/${userId}/role`, { role });
+    return response.data;
+  },
+
+  deleteUser: async (userId: number): Promise<void> => {
+    await api.delete(`/admin/users/${userId}`);
+  },
+};
+
+export default api;