Add configurable reply_to_mode for Telegram multi-chunk replies:
- off: never thread replies to original message
- first: only first chunk threads (default, preserves current behavior)
- all: all chunks thread to original message
Configurable via reply_to_mode in platform config or TELEGRAM_REPLY_TO_MODE
env var.
Cherry-picked from PR #855 by raulvidis, rebased onto current main.
Dropped asyncio_mode=auto pyproject.toml change, added @pytest.mark.asyncio
decorators, fixed test IDs to use numeric strings.
Co-authored-by: Raul <77628552+raulvidis@users.noreply.github.com>
1334d5f014