feat(story-1.4): add session-based authentication with login/logout

internal/domain/session.go

@@ -0,0 +1,27 @@
+package domain
+
+import (
+	"time"
+
+	"github.com/google/uuid"
+)
+
+// Session represents an active user session.
+type Session struct {
+	ID        uuid.UUID `json:"id"`
+	UserID    uuid.UUID `json:"user_id"`
+	Token     string    `json:"-"` // Never expose in JSON
+	ExpiresAt time.Time `json:"expires_at"`
+	CreatedAt time.Time `json:"created_at"`
+	UserAgent string    `json:"user_agent,omitempty"`
+	IPAddress string    `json:"ip_address,omitempty"`
+}
+
+// SessionRepository defines the interface for session data access.
+type SessionRepository interface {
+	Create(session *Session) error
+	GetByToken(token string) (*Session, error)
+	Delete(token string) error
+	DeleteByUserID(userID uuid.UUID) error
+	DeleteExpired() (int64, error)
+}