test(channels): add comprehensive test suites for channel adapters

- Add ChannelBase, GroupGate, SenderGate, SessionRouter tests
- Add DingTalk markdown utility tests
- Add Weixin media and send helper tests
- Add CLI channel config-utils and pidfile tests
- Configure vitest for all channel packages
- Exclude test files from TypeScript build

Tests cover attachment handling, block streaming, gating policies,
session routing, markdown conversion, config parsing, and service management.

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

packages/channels/base/vitest.config.ts

@@ -0,0 +1,8 @@
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+  test: {
+    include: ['src/**/*.test.ts'],
+    globals: true,
+  },
+});