Add complete database schema and ORM models (#4)

internal/models/auth_token.go

@@ -0,0 +1,27 @@
+package models
+
+import (
+	"context"
+	"fmt"
+	"time"
+)
+
+// AuthToken represents an authentication token for a user session.
+type AuthToken struct {
+	Base
+
+	Token      string     `json:"-"`
+	UserID     string     `json:"userId"`
+	CreatedAt  time.Time  `json:"createdAt"`
+	ExpiresAt  *time.Time `json:"expiresAt,omitempty"`
+	LastUsedAt *time.Time `json:"lastUsedAt,omitempty"`
+}
+
+// User returns the user who owns this token.
+func (t *AuthToken) User(ctx context.Context) (*User, error) {
+	if ul := t.GetUserLookup(); ul != nil {
+		return ul.GetUserByID(ctx, t.UserID)
+	}
+
+	return nil, fmt.Errorf("user lookup not available")
+}