Fix shutdown handling, error management, and process lifecycle issues

🤖 Generated with [OpenCode](https://opencode.ai)

Co-Authored-By: OpenCode <noreply@opencode.ai>

packages/opencode/src/lsp/client.ts

@@ -169,7 +169,7 @@ export namespace LSPClient {
         log.info("shutting down")
         connection.end()
         connection.dispose()
-        server.process.kill()
+        server.process.kill("SIGKILL")
       },
     }