feat: Add chat seperator and restore last viewed chat on restart

toju-app/src/app/infrastructure/persistence/README.md

@@ -6,12 +6,15 @@ Offline-first storage layer that keeps messages, users, rooms, reactions, bans,
 
 ```
 persistence/
-├── index.ts                        Barrel (exports DatabaseService)
+├── app-resume.storage.ts           localStorage helpers for launch settings and last viewed chat
+├── index.ts                        Barrel (exports DatabaseService and storage helpers)
 ├── database.service.ts              Platform-agnostic facade
 ├── browser-database.service.ts      IndexedDB backend (web)
 └── electron-database.service.ts     IPC/SQLite backend (desktop)
 ```
 
+`app-resume.storage.ts` is the one exception to the `DatabaseService` facade. It stores lightweight UI-level launch preferences and the last viewed room/channel snapshot in `localStorage`, which would be unnecessary overhead to route through IndexedDB or SQLite.
+
 ## Platform routing
 
 ```mermaid

toju-app/src/app/infrastructure/persistence/app-resume.storage.ts

@@ -0,0 +1,114 @@
+import {
+  STORAGE_KEY_GENERAL_SETTINGS,
+  STORAGE_KEY_LAST_VIEWED_CHAT
+} from '../../core/constants';
+
+export interface GeneralSettings {
+  reopenLastViewedChat: boolean;
+}
+
+export const DEFAULT_GENERAL_SETTINGS: GeneralSettings = {
+  reopenLastViewedChat: true
+};
+
+export interface LastViewedChatSnapshot {
+  userId: string;
+  roomId: string;
+  channelId: string | null;
+}
+
+export function loadGeneralSettingsFromStorage(): GeneralSettings {
+  try {
+    const raw = localStorage.getItem(STORAGE_KEY_GENERAL_SETTINGS);
+
+    if (!raw) {
+      return { ...DEFAULT_GENERAL_SETTINGS };
+    }
+
+    return normaliseGeneralSettings(JSON.parse(raw) as Partial<GeneralSettings>);
+  } catch {
+    return { ...DEFAULT_GENERAL_SETTINGS };
+  }
+}
+
+export function saveGeneralSettingsToStorage(patch: Partial<GeneralSettings>): GeneralSettings {
+  const nextSettings = normaliseGeneralSettings({
+    ...loadGeneralSettingsFromStorage(),
+    ...patch
+  });
+
+  try {
+    localStorage.setItem(STORAGE_KEY_GENERAL_SETTINGS, JSON.stringify(nextSettings));
+  } catch {}
+
+  return nextSettings;
+}
+
+export function loadLastViewedChatFromStorage(userId?: string | null): LastViewedChatSnapshot | null {
+  try {
+    const raw = localStorage.getItem(STORAGE_KEY_LAST_VIEWED_CHAT);
+
+    if (!raw) {
+      return null;
+    }
+
+    const snapshot = normaliseLastViewedChatSnapshot(JSON.parse(raw) as Partial<LastViewedChatSnapshot>);
+
+    if (!snapshot) {
+      return null;
+    }
+
+    if (userId && snapshot.userId !== userId) {
+      return null;
+    }
+
+    return snapshot;
+  } catch {
+    return null;
+  }
+}
+
+export function saveLastViewedChatToStorage(snapshot: LastViewedChatSnapshot): void {
+  const normalised = normaliseLastViewedChatSnapshot(snapshot);
+
+  if (!normalised) {
+    return;
+  }
+
+  try {
+    localStorage.setItem(STORAGE_KEY_LAST_VIEWED_CHAT, JSON.stringify(normalised));
+  } catch {}
+}
+
+export function clearLastViewedChatFromStorage(): void {
+  try {
+    localStorage.removeItem(STORAGE_KEY_LAST_VIEWED_CHAT);
+  } catch {}
+}
+
+function normaliseGeneralSettings(raw: Partial<GeneralSettings>): GeneralSettings {
+  return {
+    reopenLastViewedChat:
+      typeof raw.reopenLastViewedChat === 'boolean'
+        ? raw.reopenLastViewedChat
+        : DEFAULT_GENERAL_SETTINGS.reopenLastViewedChat
+  };
+}
+
+function normaliseLastViewedChatSnapshot(raw: Partial<LastViewedChatSnapshot>): LastViewedChatSnapshot | null {
+  const userId = typeof raw.userId === 'string' ? raw.userId.trim() : '';
+  const roomId = typeof raw.roomId === 'string' ? raw.roomId.trim() : '';
+  const channelId = typeof raw.channelId === 'string'
+    ? raw.channelId.trim() || null
+    : null;
+
+  if (!userId || !roomId) {
+    return null;
+  }
+
+  return {
+    userId,
+    roomId,
+    channelId
+  };
+}

toju-app/src/app/infrastructure/persistence/index.ts

@@ -1 +1,2 @@
+export * from './app-resume.storage';
 export * from './database.service';