Initial commit: TravelHub multi-tenant flight booking platform

Angular + Go + PostgreSQL sample with strict per-tenant isolation.

- Backend: Go API (basic auth, tenant-scoped repository layer, pgx pool)
- Frontend: Angular 22 SPA (search, checkout, bookings, dashboard)
- Database: schema, seed data and demo bookings migrations
- Tests: 311 across Go (integration), Angular (unit) and Playwright (e2e),
  plus a generated evidence report with PDF export
- Security: whitebox VAPT report under security/

Secrets (.env, tokens, DB credentials) are git-ignored.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/internal/repository/identity_repo.go

@@ -0,0 +1,72 @@
+package repository
+
+import (
+	"context"
+	"errors"
+
+	"github.com/google/uuid"
+	"github.com/jackc/pgx/v5"
+	"github.com/travelswitch/travelhub/backend/internal/models"
+)
+
+// TenantBySlug resolves the tenant a caller is signing in to. Suspended
+// tenants are treated as absent so their users cannot authenticate.
+func (r *Repository) TenantBySlug(ctx context.Context, slug string) (models.Tenant, error) {
+	const q = `
+		SELECT id, slug, name, status, created_at
+		FROM   tenants
+		WHERE  slug = $1 AND status = 'active'`
+
+	var t models.Tenant
+	err := r.pool.QueryRow(ctx, q, slug).
+		Scan(&t.ID, &t.Slug, &t.Name, &t.Status, &t.CreatedAt)
+	if errors.Is(err, pgx.ErrNoRows) {
+		return models.Tenant{}, ErrNotFound
+	}
+	return t, err
+}
+
+// ListTenants powers the tenant picker on the sign-in screen. It is the only
+// unauthenticated read in the service and deliberately exposes nothing beyond
+// the slug and display name.
+func (r *Repository) ListTenants(ctx context.Context) ([]models.Tenant, error) {
+	const q = `
+		SELECT id, slug, name, status, created_at
+		FROM   tenants
+		WHERE  status = 'active'
+		ORDER  BY name`
+
+	rows, err := r.pool.Query(ctx, q)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	tenants := []models.Tenant{}
+	for rows.Next() {
+		var t models.Tenant
+		if err := rows.Scan(&t.ID, &t.Slug, &t.Name, &t.Status, &t.CreatedAt); err != nil {
+			return nil, err
+		}
+		tenants = append(tenants, t)
+	}
+	return tenants, rows.Err()
+}
+
+// UserByEmail looks up a login within one tenant. The tenant filter is what
+// stops credentials from one agency authenticating against another.
+func (r *Repository) UserByEmail(ctx context.Context, tenantID uuid.UUID, email string) (models.User, error) {
+	const q = `
+		SELECT id, tenant_id, email, password_hash, full_name, role, created_at
+		FROM   users
+		WHERE  tenant_id = $1 AND lower(email) = lower($2)`
+
+	var u models.User
+	err := r.pool.QueryRow(ctx, q, tenantID, email).Scan(
+		&u.ID, &u.TenantID, &u.Email, &u.PasswordHash, &u.FullName, &u.Role, &u.CreatedAt,
+	)
+	if errors.Is(err, pgx.ErrNoRows) {
+		return models.User{}, ErrNotFound
+	}
+	return u, err
+}