feat(11-02): integrate stealth fingerprint masking into ZhihuCrawler

- Add stealth_config parameter to ZhihuCrawler.__init__
- Add --disable-blink-features=AutomationControlled to launch args
- Call apply_stealth_sync after browser context creation
- Maintain backward compatibility (stealth enabled by default)
- Add 8 integration tests covering stealth behavior and compatibility

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

kb_workflow/crawler/zhihu_crawler.py

@@ -35,6 +35,7 @@ from .models import (
 )
 from .config import CrawlerConfig, get_crawler_config
 from .proxy_pool import ProxyPool, ProxyEntry
+from .stealth import apply_stealth_sync, StealthConfig
 
 
 class ZhihuApiInterceptor:
@@ -108,7 +109,8 @@ class ZhihuCrawler:
         headless: bool = True,
         timeout: int = 30,
         config: Optional[CrawlerConfig] = None,
-        proxy_pool: Optional[ProxyPool] = None
+        proxy_pool: Optional[ProxyPool] = None,
+        stealth_config: Optional[StealthConfig] = None
     ):
         """Initialize ZhihuCrawler.
 
@@ -117,11 +119,13 @@ class ZhihuCrawler:
             timeout: Request timeout in seconds
             config: Optional CrawlerConfig instance (uses environment if not provided)
             proxy_pool: Optional ProxyPool instance for multi-proxy rotation
+            stealth_config: Optional StealthConfig instance (uses defaults if not provided)
         """
         self.headless = headless
         self.timeout = timeout
         self.config = config or get_crawler_config()
         self.proxy_pool = proxy_pool
+        self._stealth_config = stealth_config
         self._current_proxy: Optional[ProxyEntry] = None
         self.browser: Optional[PlaywrightBrowser] = None
         self.interceptor: Optional[ZhihuApiInterceptor] = None
@@ -155,6 +159,7 @@ class ZhihuCrawler:
         """Start browser with proxy configuration.
 
         Validates proxy if required and applies to browser context.
+        Applies stealth fingerprint masking after context creation.
         Prioritizes proxy_pool over config.proxy for multi-proxy support.
 
         Args:
@@ -166,8 +171,16 @@ class ZhihuCrawler:
         # Validate proxy configuration
         self.config.validate_proxy()
 
+        # Build launch args for stealth (add --disable-blink-features)
+        launch_args = []
+        if self._stealth_config is None or self._stealth_config.stealth_enabled:
+            launch_args.append('--disable-blink-features=AutomationControlled')
+
         self._playwright = sync_playwright().start()
-        self._browser = self._playwright.chromium.launch(headless=self.headless)
+        self._browser = self._playwright.chromium.launch(
+            headless=self.headless,
+            args=launch_args if launch_args else None
+        )
 
         # Build context options
         context_options = {
@@ -190,6 +203,9 @@ class ZhihuCrawler:
 
         self._context = self._browser.new_context(**context_options)
 
+        # Apply stealth fingerprint masking
+        apply_stealth_sync(self._context, self._stealth_config)
+
         # Add cookies if provided
         if cookie:
             self._add_cookies(cookie)