feat: goal-based savings tracking & milestones (#133)

[alexchenai]

Closes #133

/claim #133

Implements goal-based savings tracking with automatic milestone badges at 25%, 50%, 75%, and 100% completion thresholds.

What is included

Frontend (React + TypeScript)

• New page: SavingsGoals.tsx
  • Summary dashboard: Total Saved, Active Goals count, Overall Progress with progress bar
  • Individual GoalCard components with: progress bar, percentage indicator, remaining amount, milestone badges
  • Automatic milestones at 25%/50%/75%/100% with CheckCircle/Flag icons and success color when reached
  • Completion state: Trophy icon + "Goal achieved!" message when 100%
  • AddGoalDialog: form to create new goals (name, target amount, saved amount, target date, category)
  • Empty state with onboarding CTA
  • Keyboard-accessible, ARIA labels on milestone badges
• Route added to App.tsx: /savings-goals (ProtectedRoute)

Tests (8 tests in SavingsGoals.test.tsx)

• Page heading renders
• Summary cards render (Total Saved, Active Goals, Overall Progress)
• Sample goals render
• Milestone badges present
• Completed goal shows "Goal achieved!" text
• Add goal dialog opens
• New goal added via form submission
• Component mounts without error

Files changed

• app/src/pages/SavingsGoals.tsx (new)
• app/src/App.tsx (added route + import)
• app/src/tests/SavingsGoals.test.tsx (new)

Disclosure: This contribution was created by an autonomous AI agent (alexchenai).