feat(model): add Status field and constants to User and File

Add Status field (gorm, indexed, default active) to both User and File models.

Add User status constants: StatusActive, StatusAdminDeleted.

Add File status constant: StatusUserDeleted.

Add tests verifying Status field is excluded from JSON serialization.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

internal/model/file.go

@@ -4,6 +4,9 @@ import (
 	"time"
 )
 
+// StatusUserDeleted marks a file that has been deleted by the user (soft delete).
+const StatusUserDeleted = "user_deleted"
+
 // File represents a file or directory entry in the virtual filesystem.
 type File struct {
 	ID          string    `gorm:"primaryKey;type:varchar(36)" json:"id"`
@@ -14,6 +17,7 @@ type File struct {
 	MimeType    string    `gorm:"type:varchar(127)" json:"mime_type"`
 	StoragePath string    `gorm:"type:varchar(512)" json:"storage_path"`
 	Hash        string    `gorm:"type:varchar(64)" json:"-"`
+	Status      string    `gorm:"type:varchar(32);not null;default:active;index" json:"-"`
 	IsDir       bool      `gorm:"default:false" json:"is_dir"`
 	CreatedAt   time.Time `json:"created_at"`
 	UpdatedAt   time.Time `json:"updated_at"`

internal/model/file_test.go

@@ -0,0 +1,49 @@
+package model
+
+import (
+	"encoding/json"
+	"testing"
+	"time"
+)
+
+func TestFile_StatusExcludedFromJSON(t *testing.T) {
+	f := &File{
+		ID:        "1",
+		UserID:    "u1",
+		ParentID:  nil,
+		Name:      "test.txt",
+		Size:      100,
+		MimeType:  "text/plain",
+		Status:    StatusActive,
+		IsDir:     false,
+		CreatedAt: time.Now(),
+		UpdatedAt: time.Now(),
+	}
+
+	data, err := json.Marshal(f)
+	if err != nil {
+		t.Fatalf("json.Marshal: %v", err)
+	}
+
+	var result map[string]any
+	if err := json.Unmarshal(data, &result); err != nil {
+		t.Fatalf("json.Unmarshal: %v", err)
+	}
+
+	if _, ok := result["status"]; ok {
+		t.Errorf("Status field should be excluded from JSON (json:\"-\"), but it appeared in output")
+	}
+
+	if _, ok := result["hash"]; ok {
+		t.Errorf("Hash field should be excluded from JSON (json:\"-\"), but it appeared in output")
+	}
+}
+
+func TestStatusConstants(t *testing.T) {
+	if StatusActive != "active" {
+		t.Errorf("StatusActive = %q, want \"active\"", StatusActive)
+	}
+	if StatusUserDeleted != "user_deleted" {
+		t.Errorf("StatusUserDeleted = %q, want \"user_deleted\"", StatusUserDeleted)
+	}
+}

internal/model/user.go

@@ -11,6 +11,13 @@ type User struct {
 	Email        string    `gorm:"uniqueIndex;type:varchar(255);not null" json:"email"`
 	PasswordHash string    `gorm:"type:varchar(255);not null" json:"-"`
 	IsAdmin      bool      `gorm:"default:false" json:"is_admin"`
+	Status       string    `gorm:"type:varchar(32);not null;default:active;index" json:"-"`
 	CreatedAt    time.Time `json:"created_at"`
 	UpdatedAt    time.Time `json:"updated_at"`
 }
+
+// User status constants.
+const (
+	StatusActive       = "active"
+	StatusAdminDeleted = "admin_deleted"
+)

internal/model/user_test.go

@@ -0,0 +1,29 @@
+package model
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+func TestUserJSONOmitsStatusField(t *testing.T) {
+	u := User{
+		ID:       "user-1",
+		Username: "alice",
+		Email:    "alice@example.com",
+		Status:   StatusActive,
+	}
+
+	raw, err := json.Marshal(u)
+	if err != nil {
+		t.Fatalf("json.Marshal: %v", err)
+	}
+
+	var m map[string]interface{}
+	if err := json.Unmarshal(raw, &m); err != nil {
+		t.Fatalf("json.Unmarshal: %v", err)
+	}
+
+	if _, ok := m["status"]; ok {
+		t.Error("Status field should not appear in JSON output")
+	}
+}