refactor: decouple docs-site from ccw monorepo

- Remove docs-frontend.ts utility and docs proxy from server.ts
- Remove docs startup logic from serve.ts
- Delete HelpPage.tsx and /help route from frontend
- Remove help navigation entry from Sidebar.tsx
- Clean /docs proxy from vite.config.ts
- Remove docs-related scripts from package.json files
- Delete help.spec.ts E2E tests
- Remove docs-site directory (migrated to D:\ccw-doc)

The docs-site has been moved to D:\ccw-doc as a standalone Docusaurus
project with baseUrl='/' for static hosting deployment (GitHub Pages/Netlify).

ccw/tests/docs-proxy-port.test.js

@@ -1,74 +0,0 @@
-/**
- * Docs proxy (dashboard server) - configured docsPort plumbing
- *
- * Runs against the shipped runtime in `ccw/dist`.
- */
-
-import { afterEach, describe, it, mock } from 'node:test';
-import assert from 'node:assert/strict';
-import http from 'node:http';
-import { mkdtempSync, rmSync } from 'node:fs';
-import { tmpdir } from 'node:os';
-import { join } from 'node:path';
-
-const ORIGINAL_ENV = { ...process.env };
-
-const serverUrl = new URL('../dist/core/server.js', import.meta.url);
-serverUrl.searchParams.set('t', String(Date.now()));
-
-function httpGetText(url) {
-  return new Promise((resolve, reject) => {
-    const req = http.get(url, (res) => {
-      let data = '';
-      res.setEncoding('utf8');
-      res.on('data', (chunk) => (data += chunk));
-      res.on('end', () => resolve({ statusCode: res.statusCode ?? 0, body: data }));
-    });
-    req.on('error', reject);
-  });
-}
-
-describe('docs proxy port', () => {
-  afterEach(() => {
-    mock.restoreAll();
-    process.env = ORIGINAL_ENV;
-  });
-
-  it('proxies /docs/* to the configured docsPort', async () => {
-    const ccwHome = mkdtempSync(join(tmpdir(), 'ccw-docs-proxy-home-'));
-    process.env = { ...ORIGINAL_ENV, CCW_DATA_DIR: ccwHome, CCW_DISABLE_WARMUP: '1' };
-
-    const serverMod = await import(serverUrl.href);
-
-    let proxiedToUrl = null;
-    mock.method(globalThis, 'fetch', async (url) => {
-      proxiedToUrl = String(url);
-      return new Response('ok', {
-        status: 200,
-        headers: { 'content-type': 'text/plain; charset=utf-8' },
-      });
-    });
-
-    const server = await serverMod.startServer({
-      port: 0,
-      initialPath: process.cwd(),
-      frontend: 'react',
-      reactPort: 65530,
-      docsPort: 39999,
-    });
-
-    try {
-      const addr = server.address();
-      assert.equal(typeof addr, 'object');
-      assert.ok(addr);
-
-      const { statusCode, body } = await httpGetText(`http://127.0.0.1:${addr.port}/docs/zh/`);
-      assert.equal(statusCode, 200);
-      assert.equal(body, 'ok');
-      assert.equal(proxiedToUrl, 'http://localhost:39999/docs/zh/');
-    } finally {
-      await new Promise((resolve) => server.close(resolve));
-      rmSync(ccwHome, { recursive: true, force: true });
-    }
-  });
-});