Refactored resurrection functions to accept optional *sql.Conn parameter:
- Added tryResurrectParentWithConn() internal function
- Added tryResurrectParentChainWithConn() internal function
- Updated CreateIssue to use conn-based resurrection
- Updated EnsureIDs to use conn-based resurrection
This eliminates 'database is locked' errors when resurrection
happens inside an existing transaction.
Fixes bd-58c0