Templates are now loaded dynamically from data/templates/*.json
via the get_invoice_templates Tauri command instead of being
hardcoded in TypeScript. Preview and PDF renderer switch on
template.layout instead of template.id, allowing custom templates
to reuse built-in layouts with different colors.
Settings Timer tab now has daily/weekly goal hour inputs. Dashboard
shows goal progress bars and streak counter. Settings Billing tab
has rounding toggle with increment and method selectors. New
rounding.ts utility for nearest/up/down time rounding.
Import utility with CSV parser, Toggl/Clockify format mapping, and
generic CSV column mapping. Settings Data tab has import UI with
file picker, format selector, preview table, and import execution.
