fix: make SSL verification opt-in via config, extend fix to all platforms

- Add DISABLE_SSL_VERIFY = False to base_config.py (default: verification on)
- Add tools/httpx_util.py with make_async_client() factory that reads the config
- Replace all httpx.AsyncClient() call sites across all platforms (bilibili,
  weibo, zhihu, xhs, douyin, kuaishou) and crawler_util with make_async_client()
- Extends SSL fix to previously missed platforms: xhs, douyin, kuaishou

Users running behind an intercepting proxy can set DISABLE_SSL_VERIFY = True
in config/base_config.py. All other users retain certificate verification.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

media_platform/zhihu/client.py

@@ -26,6 +26,7 @@ from urllib.parse import urlencode
 import httpx
 from httpx import Response
 from playwright.async_api import BrowserContext, Page
+from tools.httpx_util import make_async_client
 from tenacity import retry, stop_after_attempt, wait_fixed
 
 import config
@@ -98,7 +99,7 @@ class ZhiHuClient(AbstractApiClient, ProxyRefreshMixin):
         # return response.text
         return_response = kwargs.pop('return_response', False)
 
-        async with httpx.AsyncClient(proxy=self.proxy, verify=False) as client:
+        async with make_async_client(proxy=self.proxy) as client:
             response = await client.request(method, url, timeout=self.timeout, **kwargs)
 
         if response.status_code != 200: