feat: add web search block functionality and integrate with existing plugins

- Introduced a new web search block plugin to handle web search queries and results.
- Updated copilot, doc block, and pro block plugins to include web search context in AI completions.
- Implemented utility functions for parsing and building web search markdown.
- Enhanced API to support web search requests and responses.
- Added configuration for web search URL and timeout settings.
- Updated size limit checks to account for web search content.

backend/worker.py

@@ -9,6 +9,7 @@ from job_handlers import (
     ocr_handler,
     pro_completion_handler,
     tts_handler,
+    web_search_handler,
 )
 from job_system import RedisJobManager, RedisWorker
 
@@ -23,6 +24,7 @@ async def main() -> None:
     manager = RedisJobManager()
     manager.register_handler("completion", completion_handler)
     manager.register_handler("pro_completion", pro_completion_handler)
+    manager.register_handler("web_search", web_search_handler)
     manager.register_handler("compress", compress_handler)
     manager.register_handler("ocr", ocr_handler)
     manager.register_handler("convert", convert_handler)