feat: add profile sync

backend/internal/profile/repository.go

@@ -0,0 +1,25 @@
+package profile
+
+import (
+	"context"
+	"database/sql"
+)
+
+type Repository struct {
+	db *sql.DB
+}
+
+func NewRepository(db *sql.DB) Repository {
+	return Repository{db: db}
+}
+
+func (r Repository) Ensure(ctx context.Context, id string, email string) error {
+	_, err := r.db.ExecContext(ctx, `
+		insert into public.profiles (id, email)
+		values ($1, $2)
+		on conflict (id) do update
+		set email = excluded.email
+		where public.profiles.email is distinct from excluded.email
+	`, id, email)
+	return err
+}