feat(hermes): add Telegram escalation adapter

[selvalabs]

Summary

• Adds a thin Telegram Bot API adapter for future internal Hermes escalation.
• Adds HERMES_TELEGRAM_* settings, disabled and empty by default.
• Documents the env vars in example env files.

Scope

• No real token/chat ID, no live Telegram delivery, no webhook, no WhatsApp, no LLM, and no deploy changes.
• The adapter is isolated and not wired into Hermes processing yet.

Validation

• uv run pytest tests/unit/test_telegram_provider.py tests/unit/test_hermes_telegram_config.py -q
• uv run ruff check .
• uv run mypy src
• uv run pytest

Closes #46
Refs #37