perf(*): bound list queries, batch fetches, harden media downloads

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

@@ -1,4 +1,10 @@
-import { enrichChat, getChat, getJob, listChats } from "$lib/api/endpoints";
+import {
+  enrichChat,
+  getChat,
+  getChatsBatch,
+  getJob,
+  listChats,
+} from "$lib/api/endpoints";
 import type { Chat, LiveEvent } from "$lib/api/types";
 import { folderContains } from "$lib/format/folders";
 import { accounts } from "$lib/stores/accounts.svelte";
@@ -245,6 +251,32 @@ function createChats() {
         })
         .catch(() => resolving.delete(id));
     },
+    ensureMany(ids: number[]) {
+      syncAccount();
+      if (account === null) {
+        return;
+      }
+      const missing = [
+        ...new Set(ids.filter((id) => !(resolving.has(id) || known(id)))),
+      ];
+      if (missing.length === 0) {
+        return;
+      }
+      for (const id of missing) {
+        resolving.add(id);
+      }
+      getChatsBatch(missing)
+        .then((fetched) => {
+          for (const chat of fetched) {
+            extra[chat.chat_id] = chat;
+          }
+        })
+        .catch(() => {
+          for (const id of missing) {
+            resolving.delete(id);
+          }
+        });
+    },
     load(folderId: number | null = folders.selectedId) {
       return load(folderId, false);
     },