feat(06-02): replace BudgetSetup with template-based month picker
- Rewrite BudgetSetup to use month picker + currency + Generate button
- Remove manual form fields (name, dates, carryover, copy-from select)
- Handle 409 conflict gracefully by calling onCreated() to refresh list
- Remove copyFrom method from budgets API (TMPL-06)
- Update BudgetSetup test to reflect new month-picker UI
- Remove copyFrom from DashboardPage test mock
- Add budget.generate, budget.month, budget.generating i18n keys (EN/DE)
- Remove budget.copyFrom and budget.setup i18n keys
Jean-Luc Makiola
7dfd04f31b