tests(backend): integration tests for DB ops

chore: run formatting

feat(frontend): persist savings goals and retirement breakdown via API

feat(backend): add CRUD handlers and routes for savings goals and retirement breakdown

feat(db): add tables for custom savings goals and retirement breakdown

feat: allow assigning colors to budget categories

fix(frontend): resolve ESLint errors in ItemsSection sorting logic

feat: add filtering and sorting to spending items table

Adjusted for consistency

Corrected frontend linting errors

Add RetirementBreakdownCard component

fix: fixed expenses to use month-specific endpoints instead of global ones

fix: make savings, savings goal, and retirement savings month-specific instead of global

fix: make monthly data independent across months with snapshots

added Settings to Summary page navigation