feat: #45 meta de poupança configurável + conquistas genéricas

- Nova tabela user_settings com savings_goal_pct (default 40%)
- API GET /api/settings, PUT /api/settings
- DashboardService inclui savings_goal_pct no payload
- DashboardHandler dispara savings_checked com goal configurado
- GameService.NotifyAction: checa pct >= goal (sem hardcode de 40%)
- SettingsView: painel META DE POUPANÇA com input configurável
- HomeView: widget mostra meta dinâmica (META: X%) e usa savingsGoal
- stores/settings.ts: store com fetch e update

Co-Authored-By: Claude Sonnet 4.6 <[email protected]>

apps/api/internal/service/settings.go

@@ -0,0 +1,30 @@
+package service
+
+import (
+	"context"
+	"errors"
+
+	"financeiro-carvalho/internal/model"
+	"financeiro-carvalho/internal/repository"
+)
+
+var ErrInvalidSavingsGoal = errors.New("savings_goal_pct must be between 1 and 100")
+
+type SettingsService struct {
+	repo repository.SettingsRepository
+}
+
+func NewSettingsService(repo repository.SettingsRepository) *SettingsService {
+	return &SettingsService{repo: repo}
+}
+
+func (s *SettingsService) Get(ctx context.Context) (*model.UserSettings, error) {
+	return s.repo.Get(ctx)
+}
+
+func (s *SettingsService) Update(ctx context.Context, in model.UserSettings) (*model.UserSettings, error) {
+	if in.SavingsGoalPct < 1 || in.SavingsGoalPct > 100 {
+		return nil, ErrInvalidSavingsGoal
+	}
+	return s.repo.Upsert(ctx, in)
+}