Rename the service to BugTrail ...

Bug + trail: the recorded trail of actions leading to the bug.
User-facing rename in the web panel shell, extension manifest/popup/
options, API title, i18n locales and README; Firefox id is now
bugtrail@gnexus.space. Internal @ltt/* package scopes unchanged.

Co-Authored-By: Claude Code <noreply@anthropic.com>