feat(reports): capacity-based utilization + report CSVs

Utilization now measures booked minutes against each member's
availability-rule capacity in the tenant timezone, replacing the
confirmed-share proxy. StaffMetric exposes booked/capacity minutes.

New endpoints: GET /v1/export/staff-report.csv (reuses StaffMetrics)
and GET /v1/export/service-report.csv (per-service bookings/cancelled/
revenue, class bookings rolled up). Export buttons on the staff
performance panel and services page.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

apps/backend/internal/export/service_test.go

@@ -8,12 +8,17 @@ import (
 	"testing"
 	"time"
 
+	"bookra/apps/backend/internal/bookings"
 	"bookra/apps/backend/internal/db"
 	"bookra/apps/backend/internal/domain"
 )
 
 var demoPrincipal = domain.Principal{Subject: "demo-owner", Role: "owner"}
 
+func newTestService(repo *db.MemoryRepository) *Service {
+	return NewService(repo, bookings.NewService(repo, nil, "http://localhost:3000"))
+}
+
 const demoTenantID = "5d6b3551-0a3e-4b86-bdf0-e9df20a47148"
 
 func readCSV(t *testing.T, buf *bytes.Buffer) [][]string {
@@ -50,7 +55,7 @@ func TestWriteBookingsCSVResolvesLabelsAndEscapes(t *testing.T) {
 	}
 
 	var buf bytes.Buffer
-	svc := NewService(repo)
+	svc := newTestService(repo)
 	from := time.Now().Add(-time.Hour)
 	to := time.Now().Add(72 * time.Hour)
 	if err := svc.WriteBookingsCSV(context.Background(), demoPrincipal, &buf, from, to); err != nil {
@@ -96,7 +101,7 @@ func TestWriteBookingsCSVRangeExcludesOutOfWindow(t *testing.T) {
 	}
 
 	var buf bytes.Buffer
-	svc := NewService(repo)
+	svc := newTestService(repo)
 	from := time.Now().Add(-time.Hour)
 	to := time.Now().Add(24 * time.Hour) // far-future booking outside
 	if err := svc.WriteBookingsCSV(context.Background(), demoPrincipal, &buf, from, to); err != nil {
@@ -112,7 +117,7 @@ func TestWriteBookingsCSVRangeExcludesOutOfWindow(t *testing.T) {
 func TestWriteCustomersCSVPagesAndStrips(t *testing.T) {
 	repo := db.NewMemoryRepository()
 	var buf bytes.Buffer
-	svc := NewService(repo)
+	svc := newTestService(repo)
 	if err := svc.WriteCustomersCSV(context.Background(), demoPrincipal, &buf); err != nil {
 		t.Fatalf("write csv: %v", err)
 	}
@@ -136,7 +141,7 @@ func TestWriteCustomersCSVPagesAndStrips(t *testing.T) {
 
 func TestExportRequiresMembership(t *testing.T) {
 	repo := db.NewMemoryRepository()
-	svc := NewService(repo)
+	svc := newTestService(repo)
 	var buf bytes.Buffer
 	err := svc.WriteCustomersCSV(context.Background(), domain.Principal{Subject: "nobody"}, &buf)
 	if err != ErrTenantMembership {
@@ -147,3 +152,96 @@ func TestExportRequiresMembership(t *testing.T) {
 	}
 }
 
+
+func TestWriteStaffReportCSV(t *testing.T) {
+	repo := db.NewMemoryRepository()
+	serviceID := "d5d76a61-3d49-467c-8dd4-bf61ee754e39"
+	staffID := "6936c444-c7d0-4a7d-b596-a9b72d2f4fc0"
+	now := time.Now().UTC()
+	seed := func(status string, offsetHours int) {
+		_, err := repo.CreateBooking(context.Background(), db.CreateBookingParams{
+			TenantID:      demoTenantID,
+			ServiceID:     &serviceID,
+			StaffID:       &staffID,
+			CustomerName:  "Report Customer",
+			CustomerEmail: "[email protected]",
+			StartsAt:      now.Add(time.Duration(offsetHours) * time.Hour),
+			EndsAt:        now.Add(time.Duration(offsetHours+1) * time.Hour),
+			Status:        status,
+			Reference:     "BK-REP-" + status,
+		})
+		if err != nil {
+			t.Fatalf("seed booking: %v", err)
+		}
+	}
+	seed("confirmed", -5)
+	seed("confirmed", -20)
+	seed("cancelled", -30)
+
+	var buf bytes.Buffer
+	svc := newTestService(repo)
+	if err := svc.WriteStaffReportCSV(context.Background(), demoPrincipal, &buf, 30); err != nil {
+		t.Fatalf("staff report csv: %v", err)
+	}
+	records := readCSV(t, &buf)
+	if len(records) != 2 {
+		t.Fatalf("expected header + 1 staff row, got %d rows", len(records))
+	}
+	row := records[1]
+	if row[0] != "Demo Stylist" {
+		t.Fatalf("expected staff name, got %q", row[0])
+	}
+	if row[1] != "3" || row[2] != "2" || row[3] != "1" {
+		t.Fatalf("expected bookings=3 completed=2 cancelled=1, got %v", row[1:4])
+	}
+	if row[4] != "120" {
+		t.Fatalf("expected 120 booked minutes, got %q", row[4])
+	}
+	if row[7] != "240000" {
+		t.Fatalf("expected 240000 revenue cents, got %q", row[7])
+	}
+}
+
+func TestWriteServiceReportCSV(t *testing.T) {
+	repo := db.NewMemoryRepository()
+	serviceID := "d5d76a61-3d49-467c-8dd4-bf61ee754e39"
+	sessionID := "4bf74c12-44dd-45ca-86bb-b104f16f2435"
+	now := time.Now().UTC()
+	seed := func(service *string, session *string, status string, ref string) {
+		_, err := repo.CreateBooking(context.Background(), db.CreateBookingParams{
+			TenantID:       demoTenantID,
+			ServiceID:      service,
+			ClassSessionID: session,
+			CustomerName:   "Svc Customer",
+			CustomerEmail:  "[email protected]",
+			StartsAt:       now.Add(-5 * time.Hour),
+			EndsAt:         now.Add(-4 * time.Hour),
+			Status:         status,
+			Reference:      ref,
+		})
+		if err != nil {
+			t.Fatalf("seed booking: %v", err)
+		}
+	}
+	seed(&serviceID, nil, "confirmed", "BK-SVC-1")
+	seed(&serviceID, nil, "cancelled", "BK-SVC-2")
+	seed(nil, &sessionID, "confirmed", "BK-SVC-3")
+
+	var buf bytes.Buffer
+	svc := newTestService(repo)
+	if err := svc.WriteServiceReportCSV(context.Background(), demoPrincipal, &buf, 30); err != nil {
+		t.Fatalf("service report csv: %v", err)
+	}
+	records := readCSV(t, &buf)
+	if len(records) != 3 {
+		t.Fatalf("expected header + service row + class row, got %d rows", len(records))
+	}
+	svcRow := records[1]
+	if svcRow[0] != "Signature treatment" || svcRow[1] != "2" || svcRow[2] != "1" || svcRow[3] != "120000" {
+		t.Fatalf("unexpected service row: %v", svcRow)
+	}
+	classRow := records[2]
+	if classRow[0] != "class sessions" || classRow[1] != "1" {
+		t.Fatalf("unexpected class row: %v", classRow)
+	}
+}