feat(frontend): storage shows the heaviest chats, a chat opens its own files with selective cleanup and a whole-chat move to trash

frontend/src/lib/stores/storage.svelte.ts

@@ -0,0 +1,26 @@
+import { ui } from "#lib/stores/ui.svelte.js";
+
+export type StorageListing = "files" | "chats";
+
+function createStorageUi() {
+  let listing = $state<StorageListing>("files");
+  let chatId = $state<number | null>(null);
+
+  return {
+    get chatId() {
+      return chatId;
+    },
+    get listing() {
+      return listing;
+    },
+    set listing(next: StorageListing) {
+      listing = next;
+    },
+    openChat(id: number) {
+      chatId = id;
+      ui.openPanel("storage-chat");
+    },
+  };
+}
+
+export const storageUi = createStorageUi();