Tags: testingbot/testingbot-gradle-plugin

Trigger publish on unprefixed version tags + manual dispatch

The release tag was '0.1.0' but the workflow only matched 'v*', so it
never fired. Accept both 'v*' and '[0-9]*' tags, add workflow_dispatch,
and guard the tag-only steps (verify tag, create release) so a manual
run also works.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>