fix: properly handle repository errors and remove unused hash field

- fix: wrap errors from sessionRepo.Delete, credentialRepo operations
  with internal error context in Logout, ListPasskeys, and RevokePasskey
- fix: remove Hash field from fileInfoResponse DTO (unused)

internal/handler/file.go

@@ -61,7 +61,6 @@ type fileInfoResponse struct {
 	Size      int64     `json:"size"`
 	MimeType  string    `json:"mime_type"`
 	IsDir     bool      `json:"is_dir"`
-	Hash      string    `json:"hash,omitempty"`
 	CreatedAt time.Time `json:"created_at"`
 	UpdatedAt time.Time `json:"updated_at"`
 }
@@ -343,7 +342,6 @@ func toFileInfoResponse(info *service.FileInfo) fileInfoResponse {
 		Size:      info.Size,
 		MimeType:  info.MimeType,
 		IsDir:     info.IsDir,
-		Hash:      info.Hash,
 		CreatedAt: info.CreatedAt,
 		UpdatedAt: info.UpdatedAt,
 	}