Bump version to 0.2.1 and derive version from release tag

The 0.2.1 release failed to publish because VERSION still said 0.2.0,
so the workflow rebuilt 0.2.0 artifacts and PyPI rejected them as
duplicates. The publish workflow now writes the release tag into
VERSION before building, making the tag the source of truth.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JwNknzz93gcE4tS4cLwNQH

Clarify who clears reconnect_after_suspend

Bump version