Remove HTTP server mode, keep MCP + CLI only

Drop express dependency and HTTP server in favor of MCP-only architecture.
CLI still works for quick screenshots and queries.

- Delete src/server.ts and src/server.test.ts
- Remove express, @types/express, supertest from dependencies
- Update CLI to show help when no URL provided
- Remove server exports from index.ts

-33 packages removed, 757 lines deleted.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/index.ts

@@ -1,5 +1,4 @@
 export { ClaudeBrowser } from './browser.js';
-export { BrowserServer, startServer } from './server.js';
 export {
   createFavicon,
   convert,
@@ -41,4 +40,3 @@ export type {
   CompressCommand,
   ThumbnailCommand,
 } from './types.js';
-export type { ServerOptions } from './server.js';