fix(restore): validate migration data before wiping database

Move archive validation (migration file existence and slice bounds
check) before the database wipe. Previously a malformed archive
would first destroy the database and then panic, leaving the
instance in an irrecoverable state with total data loss.

Now the migration data is fully parsed and validated before any
destructive operations occur.

pkg/modules/dump/restore.go

@@ -131,15 +131,14 @@ func Restore(filename string, overrideConfig bool) error {
 
 	///////
 	// Restore the db
-	// Start by wiping everything
-	if err := db.WipeEverything(); err != nil {
-		return fmt.Errorf("could not wipe database: %w", err)
-	}
-	log.Info("Wiped database.")
 
-	// Because we don't explicitly saved the table definitions, we take the last ran db migration from the dump
-	// and execute everything until that point.
+	// Validate archive contents before wiping to avoid leaving the database
+	// in a destroyed state when the archive is malformed.
 	migrations := dbfiles["migration"]
+	if migrations == nil {
+		return fmt.Errorf("dump does not contain database migration information")
+	}
+
 	rc, err := migrations.Open()
 	if err != nil {
 		return fmt.Errorf("could not open migrations: %w", err)
@@ -159,7 +158,17 @@ func Restore(filename string, overrideConfig bool) error {
 		return ms[i].ID < ms[j].ID
 	})
 
+	if len(ms) < 2 {
+		return fmt.Errorf("dump does not contain enough migration information")
+	}
+
 	lastMigration := ms[len(ms)-2]
+
+	// Start by wiping everything - only after we've validated the archive
+	if err := db.WipeEverything(); err != nil {
+		return fmt.Errorf("could not wipe database: %w", err)
+	}
+	log.Info("Wiped database.")
 	log.Debugf("Last migration: %s", lastMigration.ID)
 	if err := migration.MigrateTo(lastMigration.ID, nil); err != nil {
 		return fmt.Errorf("could not create db structure: %w", err)