When edit_message_text fails with a transient error (httpx.ConnectError,
NetworkError, server disconnected, timeouts), the progress-message sender
must not permanently set can_edit = False — that would convert a single
Telegram network hiccup into separate per-tool bubbles for the rest of the run.
Changes:
- gateway/platforms/telegram.py: edit_message now returns retryable=True for
transient network errors (ConnectError, NetworkError, timeouts, server
disconnects, temporarily unavailable). Permanent failures (flood control,
message-not-found, permissions) remain retryable=False.
- gateway/run.py: send_progress_messages checks result.retryable before
setting can_edit = False. Transient failures skip the fallback-send and
continue — the next edit cycle catches up with the accumulated lines.
Permanent failures (flood, message-not-found, etc.) still disable editing.
Tests: 22 new tests in test_telegram_progress_edit_transient.py covering
transient vs permanent error classification, SendResult.retryable semantics,
and the can_edit decision logic.
Fixes#27828
