fix: harden stripToolCallLeaks regex for CJK/non-ASCII garbage tokens

The previous regex used \w+ for descriptor tokens between the function
name and JSON body, which only matches ASCII word characters. Model
hallucinations often inject CJK/non-ASCII text (e.g. 彩神争霸) in this
position. Switch to (?:\s+[^\s{}]+)+ to match any whitespace-separated
non-brace tokens regardless of character set.

Also removes stale backward-compat re-exports from index.ts and updates
the test import for composeDashboardContent.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/index.test.ts

@@ -1,11 +1,11 @@
 import { describe, expect, it, vi } from 'vitest';
 
 import {
-  composeDashboardContent,
   editFormattedTrackedChannelMessage,
   sendFormattedChannelMessage,
   sendFormattedTrackedChannelMessage,
 } from './index.js';
+import { composeDashboardContent } from './dashboard-render.js';
 import { Channel } from './types.js';
 
 function makeChannel(overrides: Partial<Channel> = {}): Channel {