feat: Enhance Bilibili crawler with retry logic and robustness

This commit introduces several improvements to enhance the stability and functionality of the Bilibili crawler.

- **Add Retry Logic:** Implement a retry mechanism with exponential backoff when fetching video comments. This makes the crawler more resilient to transient network issues or API errors.
- **Improve Error Handling:** Add a `try...except` block to handle potential `JSONDecodeError` in the Bilibili client, preventing crashes when the API returns an invalid response.
- **Ensure Clean Shutdown:** Refactor `main.py` to use a `try...finally` block, guaranteeing that the crawler and database connections are properly closed on exit, error, or `KeyboardInterrupt`.
- **Update Default Config:** Adjust default configuration values to increase concurrency, enable word cloud generation by default, and refine the Bilibili search mode for more practical usage.

main.py

@@ -45,25 +45,29 @@ class CrawlerFactory:
         return crawler_class()
 
 async def main():
+    # Init crawler
+    crawler: Optional[AbstractCrawler] = None
+    try:
+        # parse cmd
+        await cmd_arg.parse_cmd()
 
-    # parse cmd
-    await cmd_arg.parse_cmd()
+        # init db
+        if config.SAVE_DATA_OPTION == "db":
+            await db.init_db()
 
-    # init db
-    if config.SAVE_DATA_OPTION == "db":
-        await db.init_db()
+        crawler = CrawlerFactory.create_crawler(platform=config.PLATFORM)
+        await crawler.start()
+    finally:
+        if crawler:
+            await crawler.close()
+        if config.SAVE_DATA_OPTION == "db":
+            await db.close()
 
-    crawler = CrawlerFactory.create_crawler(platform=config.PLATFORM)
-    await crawler.start()
-
-    if config.SAVE_DATA_OPTION == "db":
-        await db.close()
-
-    
 
 if __name__ == '__main__':
     try:
         # asyncio.run(main())
         asyncio.get_event_loop().run_until_complete(main())
     except KeyboardInterrupt:
+        print("\n[main] Caught keyboard interrupt, exiting.")
         sys.exit()