feat(sms): implement SMS messaging and metered billing

Implement a complete SMS messaging system including:
- Integration with SMS Manager.cz API for sending messages.
- Metered billing via Stripe using monthly aggregate invoice items.
- Backend services for managing SMS settings, usage logging, and monthly reporting.
- Database migrations for tenant settings, usage logs, and monthly reports.
- Frontend dashboard components for SMS configuration, usage tracking, and history.
- Support for customer phone numbers in the booking flow.

Includes new migrations, backend services, and frontend UI components.

apps/backend/internal/db/repository.go

@@ -86,6 +86,18 @@ type Repository interface {
 	// Working Hours
 	ListWorkingHoursByTenant(ctx context.Context, tenantID string) ([]WorkingHoursRecord, error)
 	UpdateWorkingHours(ctx context.Context, tenantID string, dayOfWeek int, params UpdateWorkingHoursParams) error
+
+	// SMS
+	GetTenantSMSSettings(ctx context.Context, tenantID string) (TenantSMSSettingsRecord, error)
+	UpsertTenantSMSSettings(ctx context.Context, params TenantSMSSettingsRecord) error
+	CreateSMSUsageLog(ctx context.Context, params SMSUsageLogRecord) (string, error)
+	GetSMSUsageThisMonth(ctx context.Context, tenantID string) (SMSUsageSummary, error)
+	GetSMSUsageForMonth(ctx context.Context, tenantID string, yearMonth string) (SMSMonthlyReportRecord, error)
+	ListSMSUsageLogs(ctx context.Context, tenantID string, limit int) ([]SMSUsageLogRecord, error)
+	ListSMSMonthlyReports(ctx context.Context, tenantID string, limit int) ([]SMSMonthlyReportRecord, error)
+	UpsertSMSMonthlyReport(ctx context.Context, params SMSMonthlyReportRecord) error
+	MarkSMSReportInvoiceSent(ctx context.Context, tenantID string, yearMonth string) error
+	ListTenantsWithSMSUsage(ctx context.Context, yearMonth string) ([]TenantRecord, error)
 }
 
 type TenantRecord struct {
@@ -124,12 +136,12 @@ type MagicLinkRecord struct {
 }
 
 type PlatformStats struct {
-	TotalTenants       int64 `json:"totalTenants"`
-	TotalUsers         int64 `json:"totalUsers"`
+	TotalTenants        int64 `json:"totalTenants"`
+	TotalUsers          int64 `json:"totalUsers"`
 	ActiveSubscriptions int64 `json:"activeSubscriptions"`
 	TrialSubscriptions  int64 `json:"trialSubscriptions"`
-	BookingsThisMonth  int64 `json:"bookingsThisMonth"`
-	RevenueThisMonth   int64 `json:"revenueThisMonthCents"`
+	BookingsThisMonth   int64 `json:"bookingsThisMonth"`
+	RevenueThisMonth    int64 `json:"revenueThisMonthCents"`
 }
 
 type AdminAuditLogParams struct {
@@ -229,6 +241,7 @@ type BookingRecord struct {
 	LocationID     *string
 	CustomerName   string
 	CustomerEmail  string
+	CustomerPhone  string
 	StartsAt       time.Time
 	EndsAt         time.Time
 	Status         string
@@ -244,6 +257,7 @@ type CreateBookingParams struct {
 	BookingMode    string
 	CustomerName   string
 	CustomerEmail  string
+	CustomerPhone  string
 	StartsAt       time.Time
 	EndsAt         time.Time
 	Status         string
@@ -414,6 +428,44 @@ type UpdateWorkingHoursParams struct {
 	IsOpen      *bool
 }
 
+// SMS Records
+type TenantSMSSettingsRecord struct {
+	TenantID                 string
+	Enabled                  bool
+	SenderName               string
+	MonthlyLimit             int
+	StripeSubscriptionItemID string
+}
+
+type SMSUsageLogRecord struct {
+	ID                string
+	TenantID          string
+	RecipientPhone    string
+	MessageBody       string
+	ExternalMessageID string
+	ExternalRequestID string
+	Status            string
+	CostCents         int
+	SentAt            time.Time
+	CreatedAt         time.Time
+}
+
+type SMSUsageSummary struct {
+	MessageCount   int
+	TotalCostCents int
+}
+
+type SMSMonthlyReportRecord struct {
+	ID              string
+	TenantID        string
+	YearMonth       string
+	MessageCount    int
+	TotalCostCents  int
+	StripeInvoiceID string
+	InvoiceSentAt   *time.Time
+	CreatedAt       time.Time
+}
+
 type PGRepository struct {
 	pool *pgxpool.Pool
 }
@@ -428,46 +480,14 @@ func NewRepository(pools *Pools, demoMode bool) Repository {
 	return NewMemoryRepository()
 }
 
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 // ============================================
 // LOCATION / ZONE METHODS - PG REPOSITORY (STUBS)
 // ============================================
 
-
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 // ============================================
 // BLOCKED DAYS METHODS - PG REPOSITORY (STUBS)
 // ============================================
 
-
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-
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 // ============================================
 // CUSTOMER METHODS - PG REPOSITORY (STUBS)
 // ============================================
@@ -572,11 +592,11 @@ func (r *PGRepository) GetBookingByReference(ctx context.Context, reference stri
 	var rec BookingRecord
 	err := r.pool.QueryRow(ctx, `
 		SELECT id, tenant_id, service_id, class_session_id, staff_id, location_id,
-		       customer_name, customer_email, starts_at, ends_at, status, reference
+		       customer_name, customer_email, customer_phone, starts_at, ends_at, status, reference
 		FROM bookings
 		WHERE reference = $1
 	`, reference).Scan(&rec.ID, &rec.TenantID, &rec.ServiceID, &rec.ClassSessionID, &rec.StaffID, &rec.LocationID,
-		&rec.CustomerName, &rec.CustomerEmail, &rec.StartsAt, &rec.EndsAt, &rec.Status, &rec.Reference)
+		&rec.CustomerName, &rec.CustomerEmail, &rec.CustomerPhone, &rec.StartsAt, &rec.EndsAt, &rec.Status, &rec.Reference)
 	return rec, err
 }
 
@@ -598,8 +618,6 @@ func (r *PGRepository) RescheduleBooking(ctx context.Context, bookingID string,
 // WORKING HOURS METHODS - PG REPOSITORY (STUBS)
 // ============================================
 
-
-
 type MemoryRepository struct {
 	tenant          TenantRecord
 	membership      TenantMembershipRecord
@@ -617,6 +635,9 @@ type MemoryRepository struct {
 	blockedDays     []BlockedDayRecord
 	customers       []CustomerRecord
 	workingHours    []WorkingHoursRecord
+	smsSettings     TenantSMSSettingsRecord
+	smsLogs         []SMSUsageLogRecord
+	smsReports      []SMSMonthlyReportRecord
 }
 
 func NewMemoryRepository() *MemoryRepository {