fix: Resolve unexpected BrowserContext closure during crawl in Docker

- Removed __del__ method in AsyncPlaywrightCrawlerStrategy to ensure reliable browser lifecycle management by using explicit context managers.
- Added process monitoring in ManagedBrowser to detect and log unexpected terminations of the browser subprocess.
- Updated Docker configuration to expose port 9222 for remote debugging and allocate extra shared memory to prevent browser crashes.
- Improved error handling and resource cleanup for browser instances, particularly in Docker environments.

Resolves Issue #256

Dockerfile

@@ -115,7 +115,12 @@ HEALTHCHECK --interval=30s --timeout=30s --start-period=5s --retries=3 \
     CMD curl -f http://localhost:8000/health || exit 1
 
 # Expose port
-EXPOSE 8000
+EXPOSE 8000 11235 9222 8080
+
+# Optional: Increase shared memory size to prevent browser crashes
+# when loading heavy pages
+RUN mkdir /dev/shm
+VOLUME /dev/shm
 
 # Start the FastAPI server
 CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "11235"]