refactor(web): move the produced-files row into its own plugin package

ui-conversation now owns only the conversation.chat.turnTail hole; the row,
its derivation, and its copy live in @deepseek-ai/dsh-client-ui-deliverables,
composed in or out by one cordis.yml line.

tsconfig.client.json

@@ -56,6 +56,7 @@
     { "path": "./packages/client/ui-layout" },
     { "path": "./packages/client/ui-sidebar" },
     { "path": "./packages/client/ui-conversation" },
+    { "path": "./packages/client/ui-deliverables" },
     { "path": "./packages/client/ui-workspace" },
     { "path": "./packages/client/ui-slash" },
     { "path": "./packages/client/ui-command" },