db: fix migration runner to handle existing DB without checksum col

internal/db/db.go

@@ -96,10 +96,30 @@ func (db *DB) runMigrationsInternal(mfs embedFS, migrationsRoot string) error {
 			return fmt.Errorf("applying migration %s: %w", name, err)
 		}
 
-		if _, err := tx.Exec(
-			"INSERT INTO schema_migrations (version, checksum) VALUES (?, ?)",
-			name, checksumHex,
-		); err != nil {
+		var insertSQL string
+		var insertArgs []interface{}
+		insertArgs = append(insertArgs, name)
+		hasChecksum := false
+		rows, _ := tx.Query("PRAGMA table_info(schema_migrations)")
+		if rows != nil {
+			for rows.Next() {
+				var cid int
+				var cname string
+				rows.Scan(&cid, &cname, new(string), new(int), new(interface{}), new(int))
+				if cname == "checksum" {
+					hasChecksum = true
+				}
+			}
+			rows.Close()
+		}
+		if hasChecksum {
+			insertSQL = "INSERT INTO schema_migrations (version, checksum) VALUES (?, ?)"
+			insertArgs = append(insertArgs, checksumHex)
+		} else {
+			insertSQL = "INSERT INTO schema_migrations (version) VALUES (?)"
+		}
+
+		if _, err := tx.Exec(insertSQL, insertArgs...); err != nil {
 			tx.Rollback()
 			return fmt.Errorf("recording migration %s: %w", name, err)
 		}