feat(14.1-01): add OAuth identities table and empty-list Index

- Model golem15_user_oauth_identities with Encrypted tokens and empty Fillable
- gormigrate 202610050001 with both unique indexes, cascade FK, and jsonb profile_data
- OAuthIdentitiesIndex returns {"data":[]} for a signed-in caller with no rows

models/oauth_identity.go

@@ -0,0 +1,32 @@
+package models
+
+import (
+	"time"
+
+	"git.golem15.com/golem15/summercms/modules/lagoon"
+)
+
+// OAuthIdentity is one linked social-login provider for a user.
+type OAuthIdentity struct {
+	ID             uint                            `gorm:"column:id;primaryKey"`
+	UserID         uint                            `gorm:"column:user_id"`
+	Provider       string                          `gorm:"column:provider"`
+	ProviderID     string                          `gorm:"column:provider_id"`
+	AccessToken    lagoon.Encrypted                `gorm:"column:access_token" json:"-"`
+	RefreshToken   lagoon.Encrypted                `gorm:"column:refresh_token" json:"-"`
+	TokenExpiresAt *time.Time                      `gorm:"column:token_expires_at"`
+	ProfileData    lagoon.Jsonable[map[string]any] `gorm:"column:profile_data"`
+	LinkedAt       *time.Time                      `gorm:"column:linked_at"`
+	CreatedAt      time.Time                       `gorm:"column:created_at"`
+	UpdatedAt      time.Time                       `gorm:"column:updated_at"`
+}
+
+func (OAuthIdentity) TableName() string { return "golem15_user_oauth_identities" }
+
+func (OAuthIdentity) Fillable() []string { return []string{} }
+
+func (OAuthIdentity) Hidden() []string {
+	return []string{"access_token", "refresh_token", "profile_data"}
+}
+
+func init() { Register(OAuthIdentity{}) }