feat(features): add TaskToastManager for consolidated task notifications

- Create task-toast-manager feature with singleton pattern

- Show running task list (newest first) when new task starts

- Track queued tasks status from ConcurrencyManager

- Integrate with BackgroundManager and sisyphus-task tool

🤖 Generated with [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode) assistance

src/index.ts

@@ -66,6 +66,7 @@ import {
 } from "./tools";
 import { BackgroundManager } from "./features/background-agent";
 import { SkillMcpManager } from "./features/skill-mcp-manager";
+import { initTaskToastManager } from "./features/task-toast-manager";
 import { type HookName } from "./config";
 import { log, detectExternalNotificationPlugin, getNotificationConflictWarning } from "./shared";
 import { loadPluginConfig } from "./plugin-config";
@@ -207,6 +208,8 @@ const OhMyOpenCodePlugin: Plugin = async (ctx) => {
 
   const backgroundManager = new BackgroundManager(ctx);
 
+  initTaskToastManager(ctx.client);
+
   const todoContinuationEnforcer = isHookEnabled("todo-continuation-enforcer")
     ? createTodoContinuationEnforcer(ctx, { backgroundManager })
     : null;