fix: preserve plugin tool state.attachments in UI and materializer (#2367)

* preserve attachments in UI and materializer

* add support for non-image attachments

* preserve attachments in UI and materializer

* improve attachment rendering and state synchronization

* simplify attachment filtering and key handling

* prevent rendering tool attachments without URLs

* require `f.url` in `imageAttachments` to match gallery indices

packages/ui/src/lib/i18n/messages/uk.ts

@@ -2035,6 +2035,7 @@ export const dict: Record<I18nKey, string> = {
   "chat.toolPart.copiedOutput": "Вивід скопійовано",
   "chat.toolPart.copyOutputFailed": "Не вдалося скопіювати вивід",
   "chat.toolPart.openSubtask": "Відкрити підзавдання {type}",
+  "chat.toolPart.attachmentFallback": "Вкладення",
   "chat.todo.total": "Усього",
   "chat.todo.inProgress": "В роботі",
   "chat.todo.pending": "В очікуванні",