Fix Telegram delivery reliability

[codeaholicguy]

Summary

• fall back to plain Telegram sends when Markdown-to-HTML formatting throws
• parse list item block tokens in Telegram HTML rendering so nested lists do not crash rich formatting
• only advance the channel runner cursor after skipped messages or successful Telegram sends, so failed sends retry

Validation

• git diff --check passed
• npm test --workspace @ai-devkit/channel-connector -- --runInBand blocked: vitest not found
• npm test --workspace packages/cli -- --runInBand blocked: vitest not found
• npm run typecheck --workspace @ai-devkit/channel-connector blocked by missing deps/types: Node types, telegraf, marked
• npm run typecheck --workspace packages/cli blocked: package has no typecheck script