fix(auth): wiring Auth/Sessions, нормализация email, GetUserByID для /me, 409 на дубль, timing-guard логина

internal/store/tenant.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/google/uuid"
 	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgconn"
 	"github.com/jackc/pgx/v5/pgtype"
 
 	"github.com/vasyakrg/dns-autoresolver/internal/provider"
@@ -14,6 +15,11 @@ import (
 	"github.com/vasyakrg/dns-autoresolver/internal/store/dto"
 )
 
+// ErrEmailTaken is returned by RegisterUser when the email is already
+// registered — a UNIQUE constraint violation (pgerrcode 23505) on
+// users.email.
+var ErrEmailTaken = errors.New("store: email already registered")
+
 // Account/Template/Domain are provider-neutral domain structs returned by the
 // thin wrappers below, so callers (internal/api) never need to import
 // internal/store/db directly.
@@ -279,6 +285,17 @@ func (s *Store) GetUserByEmail(ctx context.Context, email string) (User, error)
 	return toUser(u), nil
 }
 
+// GetUserByID looks up a user by primary key — used by handleMe (Task 3
+// hardening) to return the authenticated caller's real email instead of
+// leaving it blank.
+func (s *Store) GetUserByID(ctx context.Context, id uuid.UUID) (User, error) {
+	u, err := s.q.GetUserByID(ctx, id)
+	if err != nil {
+		return User{}, err
+	}
+	return toUser(u), nil
+}
+
 func (s *Store) CreateProjectForUser(ctx context.Context, userID uuid.UUID, name string) (Project, error) {
 	p, err := s.q.CreateProject(ctx, db.CreateProjectParams{ID: uuid.New(), UserID: userID, Name: name})
 	if err != nil {
@@ -337,6 +354,10 @@ func (s *Store) RegisterUser(ctx context.Context, email, passwordHash string) (U
 	uid := uuid.New()
 	dbu, err := q.CreateUser(ctx, db.CreateUserParams{ID: uid, Email: email, PasswordHash: ptr(passwordHash)})
 	if err != nil {
+		var pgErr *pgconn.PgError
+		if errors.As(err, &pgErr) && pgErr.Code == "23505" {
+			return User{}, Project{}, ErrEmailTaken
+		}
 		return User{}, Project{}, err
 	}
 	dbp, err := q.CreateProject(ctx, db.CreateProjectParams{ID: uuid.New(), UserID: uid, Name: "default"})