Add MCP server for AI agents

Expose webshare_search, webshare_get_link, and webshare_login_check over
stdio via the Model Context Protocol SDK. Document client configuration.

__tests__/mcp-server.test.js

@@ -0,0 +1,19 @@
+const { formatSize, createWebshareMcpServer } = require('../src/mcp-server');
+
+describe('formatSize', () => {
+  it('formats bytes', () => {
+    expect(formatSize(0)).toBe('0 B');
+    expect(formatSize(512)).toBe('512 B');
+    expect(formatSize(1024)).toBe('1.0 KB');
+    expect(formatSize(1536)).toBe('1.5 KB');
+    expect(formatSize(1024 * 1024)).toBe('1.0 MB');
+  });
+});
+
+describe('createWebshareMcpServer', () => {
+  it('creates a server instance with credentials', () => {
+    const server = createWebshareMcpServer({ username: 'u', password: 'p' });
+    expect(server).toBeDefined();
+    expect(server.server).toBeDefined();
+  });
+});