test: fix test suite compatibility with Telethon 1.36 and mock edge cases

test(conftest): explicitly mock cleanup_client_handlers as synchronous

fix(utils): tighten keyword matching in is_session_revoked_error

fix(monitor): return handler ref and guard error notification send

Add comprehensive test suite for all system modules

chore: remove temporary test files

chore: remove temporary test files

fix: correct mock_telegram_client fixture for is_connected()

fix: handle is_connected() compatibility in async context

Add CLI interface for operations without bot

Update Validation to use constants

Update Telbot to use constants

Update Monitor to use constants

Update Handlers to use constants

Update Client to use constants