feat: add stealth mode and enhance undetected browser support

- Add playwright-stealth integration with enable_stealth parameter in BrowserConfig
- Merge undetected browser strategy into main async_crawler_strategy.py using adapter pattern
- Add browser adapters (BrowserAdapter, PlaywrightAdapter, UndetectedAdapter) for flexible browser switching
- Update install.py to install both playwright and patchright browsers automatically
- Add comprehensive documentation for anti-bot features (stealth mode + undetected browser)
- Create examples demonstrating stealth mode usage and comparison tests
- Update pyproject.toml and requirements.txt with patchright>=1.49.0 and other dependencies
- Remove duplicate/unused dependencies (alphashape, cssselect, pyperclip, shapely, selenium)
- Add dependency checker tool in tests/check_dependencies.py

Breaking changes: None - all existing functionality preserved

🤖 Generated with [Claude Code](https://claude.ai/code)

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

docs/md_v2/core/browser-crawler-config.md

@@ -29,6 +29,7 @@ class BrowserConfig:
         text_mode=False,
         light_mode=False,
         extra_args=None,
+        enable_stealth=False,
         # ... other advanced parameters omitted here
     ):
         ...
@@ -84,6 +85,11 @@ class BrowserConfig:
     - Additional flags for the underlying browser.  
     - E.g. `["--disable-extensions"]`.
 
+11. **`enable_stealth`**:  
+    - If `True`, enables stealth mode using playwright-stealth.  
+    - Modifies browser fingerprints to avoid basic bot detection.  
+    - Default is `False`. Recommended for sites with bot protection.
+
 ### Helper Methods
 
 Both configuration classes provide a `clone()` method to create modified copies:

docs/md_v2/core/examples.md

@@ -28,11 +28,8 @@ This page provides a comprehensive list of example scripts that demonstrate vari
 | Example | Description | Link |
 |---------|-------------|------|
 | Deep Crawling | An extensive tutorial on deep crawling capabilities, demonstrating BFS and BestFirst strategies, stream vs. non-stream execution, filters, scorers, and advanced configurations. | [View Code](https://github.com/unclecode/crawl4ai/blob/main/docs/examples/deepcrawl_example.py) |
-<<<<<<< HEAD
 | Virtual Scroll | Comprehensive examples for handling virtualized scrolling on sites like Twitter, Instagram. Demonstrates different scrolling scenarios with local test server. | [View Code](https://github.com/unclecode/crawl4ai/blob/main/docs/examples/virtual_scroll_example.py) |
-=======
 | Adaptive Crawling | Demonstrates intelligent crawling that automatically determines when sufficient information has been gathered. | [View Code](https://github.com/unclecode/crawl4ai/blob/main/docs/examples/adaptive_crawling/) |
->>>>>>> feature/progressive-crawling
 | Dispatcher | Shows how to use the crawl dispatcher for advanced workload management. | [View Code](https://github.com/unclecode/crawl4ai/blob/main/docs/examples/dispatcher_example.py) |
 | Storage State | Tutorial on managing browser storage state for persistence. | [View Guide](https://github.com/unclecode/crawl4ai/blob/main/docs/examples/storage_state_tutorial.md) |
 | Network Console Capture | Demonstrates how to capture and analyze network requests and console logs. | [View Code](https://github.com/unclecode/crawl4ai/blob/main/docs/examples/network_console_capture_example.py) |
@@ -57,6 +54,16 @@ This page provides a comprehensive list of example scripts that demonstrate vari
 | Crypto Analysis | Demonstrates how to crawl and analyze cryptocurrency data. | [View Code](https://github.com/unclecode/crawl4ai/blob/main/docs/examples/crypto_analysis_example.py) |
 | SERP API | Demonstrates using Crawl4AI with search engine result pages. | [View Code](https://github.com/unclecode/crawl4ai/blob/main/docs/examples/serp_api_project_11_feb.py) |
 
+## Anti-Bot & Stealth Features
+
+| Example | Description | Link |
+|---------|-------------|------|
+| Stealth Mode Quick Start | Five practical examples showing how to use stealth mode for bypassing basic bot detection. | [View Code](https://github.com/unclecode/crawl4ai/blob/main/docs/examples/stealth_mode_quick_start.py) |
+| Stealth Mode Comprehensive | Comprehensive demonstration of stealth mode features with bot detection testing and comparisons. | [View Code](https://github.com/unclecode/crawl4ai/blob/main/docs/examples/stealth_mode_example.py) |
+| Undetected Browser | Simple example showing how to use the undetected browser adapter. | [View Code](https://github.com/unclecode/crawl4ai/blob/main/docs/examples/hello_world_undetected.py) |
+| Undetected Browser Demo | Basic demo comparing regular and undetected browser modes. | [View Code](https://github.com/unclecode/crawl4ai/blob/main/docs/examples/undetected_simple_demo.py) |
+| Undetected Tests | Advanced tests comparing regular vs undetected browsers on various bot detection services. | [View Folder](https://github.com/unclecode/crawl4ai/tree/main/docs/examples/undetectability/) |
+
 ## Customization & Security
 
 | Example | Description | Link |

docs/md_v2/core/installation.md

@@ -18,7 +18,7 @@ crawl4ai-setup
 ```
 
 **What does it do?**
-- Installs or updates required Playwright browsers (Chromium, Firefox, etc.)
+- Installs or updates required browser dependencies for both regular and undetected modes
 - Performs OS-level checks (e.g., missing libs on Linux)
 - Confirms your environment is ready to crawl