flaggedTransactionIds

Evidence-tray flag state for captured network transactions, durable via EvidenceStore -- the same store the dashboard's evidence tray reads and writes, so a flag made on this device and one made from the browser are the same fact rather than two independent copies. Defaults to empty so every existing adapter/fake keeps compiling; only an adapter with a durable EvidenceStore (see FullInspectorDataSource) needs to override it.