feat(frontend): main menu lists accounts with their avatars, switching opens the last chat of that account

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

@@ -5,8 +5,21 @@ import {
 } from "#lib/api/endpoints.js";
 import type { Account } from "#lib/api/types.js";
 import { browser } from "$app/env";
+import { goto } from "$app/navigation";
 
 const STORAGE_KEY = "bg.account";
+const LAST_CHAT_KEY = "bg.lastChat";
+
+function readLastChats(): Record<string, number> {
+  if (!browser) {
+    return {};
+  }
+  try {
+    return JSON.parse(localStorage.getItem(LAST_CHAT_KEY) ?? "{}");
+  } catch {
+    return {};
+  }
+}
 
 function readSelected(): number | null {
   if (!browser) {
@@ -20,6 +33,7 @@ function createAccounts() {
   let list = $state<Account[]>([]);
   let selectedId = $state<number | null>(readSelected());
   let loaded = $state(false);
+  const lastChats = readLastChats();
 
   const selected = $derived(
     list.find((account) => account.account_id === selectedId) ?? null
@@ -67,6 +81,17 @@ function createAccounts() {
       }
       await load();
     },
+    rememberChat(chatId: number | null) {
+      if (selectedId === null || !browser) {
+        return;
+      }
+      if (chatId === null) {
+        delete lastChats[selectedId];
+      } else {
+        lastChats[selectedId] = chatId;
+      }
+      localStorage.setItem(LAST_CHAT_KEY, JSON.stringify(lastChats));
+    },
     async renameDevice(id: number, deviceModel: string) {
       const updated = await renameAccountDevice(id, deviceModel);
       list = list.map((account) =>
@@ -80,6 +105,14 @@ function createAccounts() {
     get selectedId() {
       return selectedId;
     },
+    switchTo(id: number) {
+      if (id === selectedId) {
+        return;
+      }
+      select(id);
+      const chatId = lastChats[id];
+      goto(chatId === undefined ? "/app" : `/app/${chatId}`);
+    },
   };
 }