Add checkForExistingIDs check to transaction-based batch creation
(sqliteTxStorage.CreateIssues) before calling insertIssues. This
prevents INSERT OR IGNORE from silently skipping duplicate IDs,
which would cause FK constraint failures when recording events
for issues that weren't actually inserted.
Also fixes unrelated test bug: renamed parseCommaSeparated to
parseCommaSeparatedList in validators_test.go.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
5605e590a3