feat: Add Wild Central web app (Central-only UI)

Extract Central pages from the wild-cloud web app into a standalone
React app for Wild Central. Includes:

- Central overview, DNS, DHCP, Firewall, VPN, Ingress, CrowdSec pages
- Simplified sidebar with Central-only navigation
- Branding updated to "Wild Central"
- All Cloud-specific pages, components, hooks, and API services removed
- TypeScript type-check and production build pass

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

web/src/services/api/client.ts

@@ -0,0 +1,142 @@
+export class ApiError extends Error {
+  statusCode: number;
+  details?: unknown;
+
+  constructor(
+    message: string,
+    statusCode: number,
+    details?: unknown
+  ) {
+    super(message);
+    this.name = 'ApiError';
+    this.statusCode = statusCode;
+    this.details = details;
+  }
+}
+
+interface ErrorResponseBody {
+  error?: string;
+  details?: unknown;
+}
+
+import { getApiBaseUrl } from './config';
+
+export class ApiClient {
+  private baseUrl: string;
+
+  constructor(baseUrl: string = getApiBaseUrl()) {
+    this.baseUrl = baseUrl;
+  }
+
+  getBaseURL(): string {
+    return this.baseUrl;
+  }
+
+  private async request<T>(
+    endpoint: string,
+    options?: RequestInit
+  ): Promise<T> {
+    const url = `${this.baseUrl}${endpoint}`;
+
+    try {
+      const response = await fetch(url, {
+        ...options,
+        headers: {
+          'Content-Type': 'application/json',
+          ...options?.headers,
+        },
+      });
+
+      if (!response.ok) {
+        const errorData: ErrorResponseBody = await response.json().catch(() => ({}));
+        throw new ApiError(
+          errorData.error || `HTTP ${response.status}: ${response.statusText}`,
+          response.status,
+          errorData
+        );
+      }
+
+      // Handle 204 No Content — intentional no-data for void operations
+      if (response.status === 204) {
+        return undefined as unknown as T;
+      }
+
+      return response.json();
+    } catch (error) {
+      if (error instanceof ApiError) {
+        throw error;
+      }
+      throw new ApiError(
+        error instanceof Error ? error.message : 'Network error',
+        0
+      );
+    }
+  }
+
+  async get<T>(endpoint: string): Promise<T> {
+    return this.request<T>(endpoint, { method: 'GET' });
+  }
+
+  async post<T>(endpoint: string, data?: unknown): Promise<T> {
+    return this.request<T>(endpoint, {
+      method: 'POST',
+      body: data ? JSON.stringify(data) : undefined,
+    });
+  }
+
+  async put<T>(endpoint: string, data?: unknown): Promise<T> {
+    return this.request<T>(endpoint, {
+      method: 'PUT',
+      body: data ? JSON.stringify(data) : undefined,
+    });
+  }
+
+  async patch<T>(endpoint: string, data?: unknown): Promise<T> {
+    return this.request<T>(endpoint, {
+      method: 'PATCH',
+      body: data ? JSON.stringify(data) : undefined,
+    });
+  }
+
+  async delete<T>(endpoint: string): Promise<T> {
+    return this.request<T>(endpoint, { method: 'DELETE' });
+  }
+
+  async getText(endpoint: string): Promise<string> {
+    const url = `${this.baseUrl}${endpoint}`;
+    const response = await fetch(url);
+
+    if (!response.ok) {
+      const errorData = await response.json().catch(() => ({}));
+      throw new ApiError(
+        errorData.error || `HTTP ${response.status}: ${response.statusText}`,
+        response.status,
+        errorData
+      );
+    }
+
+    return response.text();
+  }
+
+  async putText(endpoint: string, text: string): Promise<{ message?: string; [key: string]: unknown }> {
+    const url = `${this.baseUrl}${endpoint}`;
+    const response = await fetch(url, {
+      method: 'PUT',
+      headers: { 'Content-Type': 'text/plain' },
+      body: text,
+    });
+
+    if (!response.ok) {
+      const errorData = await response.json().catch(() => ({}));
+      throw new ApiError(
+        errorData.error || `HTTP ${response.status}: ${response.statusText}`,
+        response.status,
+        errorData
+      );
+    }
+
+    return response.json();
+  }
+}
+
+export const apiClient = new ApiClient();