fix(telegram): split long messages to avoid Message is too long error

Telegram has a 4096 character limit per message. This fix:
- Splits messages longer than 4000 chars into multiple chunks
- Prefers breaking at newline boundaries to preserve formatting
- Falls back to space boundaries if no newlines available
- Forces split at max length if no good boundaries exist
- Adds comprehensive tests for message splitting logic

.gitignore

@@ -19,4 +19,4 @@ __pycache__/
 poetry.lock
 .pytest_cache/
 botpy.log
-tests/
+