v0.12.8: complete cross-drive backup + per-tier UI

- Cross-drive now copies DB dumps (_db/) and config (_config/) alongside user data
- restic cross-drive includes config dir + full DB dump dir
- UI: per-tier rows (1. mentés / 2. mentés) instead of per-layer (DB/Konfig/Data)
- UI: BackupContents label shows what each tier protects (DB + Konfig + Adatok)
- UI: rsync backups show browsable indicator (📁)
- Cleanup: removed unused filterSnapshotsByPaths + pathCovers from router.go

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

controller/cmd/controller/main.go

@@ -138,6 +138,7 @@ func main() {
 	if backupMgr != nil {
 		crossDriveRunner.SetDBDumper(backupMgr)
 	}
+	crossDriveRunner.SetDBDumpDir(cfg.Paths.DBDumpDir)
 
 	// --- Initialize alert manager ---
 	alertMgr := web.NewAlertManager(logger)