feat(#19): registro manual de transações e recorrências fixas

Adiciona CRUD manual de transações (income/expense) com filtro mensal, CRUD de
recorrências fixas com verificação mensal de cobertura (±10% por categoria),
endpoint de ignore/unignore e telas Vue para Transações e Configurações.

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

apps/api/internal/model/recurring.go

@@ -0,0 +1,29 @@
+package model
+
+import "time"
+
+type RecurringExpense struct {
+	ID             int       `json:"id"`
+	Name           string    `json:"name"`
+	ExpectedAmount float64   `json:"expected_amount"`
+	DayOfMonth     int       `json:"day_of_month"`
+	CategoryID     *int      `json:"category_id"`
+	Active         bool      `json:"active"`
+	CreatedAt      time.Time `json:"created_at"`
+	UpdatedAt      time.Time `json:"updated_at"`
+}
+
+type RecurringInput struct {
+	Name           string  `json:"name"`
+	ExpectedAmount float64 `json:"expected_amount"`
+	DayOfMonth     int     `json:"day_of_month"`
+	CategoryID     *int    `json:"category_id"`
+}
+
+// RecurringStatus reports whether a recurring expense is covered for a month.
+type RecurringStatus struct {
+	RecurringExpense
+	Covered bool   `json:"covered"`  // has a matching transaction
+	Ignored bool   `json:"ignored"`  // user explicitly ignored this month
+	Reason  string `json:"reason,omitempty"`
+}