v2.10.0

Added

• Header row field in import form -- The modal and standalone new import forms show a "Header row" input for CSV and XLSX sources. Users enter a 1-based row number, stored as a 0-based config["header_row"]. The field is pre-filled from the Target's header_row DSL value, exposed by Registry.available as header_row

Fixed

• Import params on inline edit -- RecordUpdater now hydrates import_params on the target before revalidating, so validations depending on them no longer fail on valid records (#3)
• File extension validation -- The uploaded file extension is cross-checked against the selected source type before saving, surfacing mismatches as a form error instead of crashing the parser (#4)