v0.78.0

Added

• Budget → Statistics tab: new dedicated view with weekly/monthly/yearly range buttons, a period stepper, summary cards for income/expense/balance plus comparison against the previous period, an SVG trend chart of income vs. expenses, category bars, an expense-share donut, and a CSV-export button for the active range. Translated for all 20 locales.
• GET /api/v1/budget/stats: new endpoint backing the Statistics tab — ?range=week|month|year&anchor=YYYY-MM-DD returns totals, prior-period comparison, per-period series, and per-category breakdown.

Changed

• GET /api/v1/budget/export: also accepts ?from=YYYY-MM-DD&to=YYYY-MM-DD to export an arbitrary date range; the legacy ?month=YYYY-MM form keeps working.