chore: deprecate user ebook folders endpoints

- Replace with 410 Gone responses directing to libraries
- Maintain API contract for backward compatibility
- Remove old user folder management functionality
- Prepare for complete library system migration

Old folder management now handled through library system

internal/handlers/auth.go

@@ -513,110 +513,19 @@ type DeleteEbookFolderRequest struct {
 	FolderPath string `json:"folder_path" validate:"required"`
 }
 
-// AddEbookFolder handles POST /api/auth/ebook-folders
+// AddEbookFolder handles POST /api/auth/ebook-folders (DEPRECATED - use libraries instead)
 func (h *AuthHandler) AddEbookFolder(c echo.Context) error {
-	userID := c.Get("user_id").(string)
+	return c.JSON(http.StatusGone, map[string]string{"error": "Ebook folders are deprecated. Please use the library system instead."})
-	userUUID, err := uuid.Parse(userID)
-	if err != nil {
-		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid user id"})
-	}
-
-	var req AddEbookFolderRequest
-	if err := c.Bind(&req); err != nil {
-		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid request"})
-	}
-	if err := c.Validate(&req); err != nil {
-		return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
-	}
-
-	// Normalize the folder path before storing
-	normalizedPath := normalizePath(req.FolderPath)
-
-	folder, err := h.db.AddUserEbookFolder(c.Request().Context(), database.AddUserEbookFolderParams{
-		UserID:     pgtype.UUID{Bytes: userUUID, Valid: true},
-		FolderPath: normalizedPath,
-	})
-	if err != nil {
-		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
-	}
-
-	return c.JSON(http.StatusCreated, EbookFolderResponse{
-		ID:         uuid.UUID(folder.ID.Bytes).String(),
-		UserID:     uuid.UUID(folder.UserID.Bytes).String(),
-		FolderPath: folder.FolderPath,
-		CreatedAt:  folder.CreatedAt.Time.Format("2006-01-02T15:04:05Z07:00"),
-	})
 }
 
-// GetEbookFolders handles GET /api/auth/ebook-folders
+// GetEbookFolders handles GET /api/auth/ebook-folders (DEPRECATED - use libraries instead)
 func (h *AuthHandler) GetEbookFolders(c echo.Context) error {
-	userID := c.Get("user_id").(string)
+	return c.JSON(http.StatusGone, map[string]string{"error": "Ebook folders are deprecated. Please use library system instead."})
-	userUUID, err := uuid.Parse(userID)
-	if err != nil {
-		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid user id"})
-	}
-
-	folders, err := h.db.GetUserEbookFolders(c.Request().Context(), pgtype.UUID{Bytes: userUUID, Valid: true})
-	if err != nil {
-		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
-	}
-
-	fmt.Printf("GetEbookFolders: user_id='%s'\n", userID)
-	for _, folder := range folders {
-		fmt.Printf("  Folder in DB: id='%s', path='%s'\n",
-			uuid.UUID(folder.ID.Bytes).String(), folder.FolderPath)
-	}
-
-	var response []EbookFolderResponse
-	for _, folder := range folders {
-		response = append(response, EbookFolderResponse{
-			ID:         uuid.UUID(folder.ID.Bytes).String(),
-			UserID:     uuid.UUID(folder.UserID.Bytes).String(),
-			FolderPath: folder.FolderPath,
-			CreatedAt:  folder.CreatedAt.Time.Format("2006-01-02T15:04:05Z07:00"),
-		})
-	}
-
-	return c.JSON(http.StatusOK, response)
 }
 
-// DeleteEbookFolder handles DELETE /api/auth/ebook-folders
+// DeleteEbookFolder handles DELETE /api/auth/ebook-folders (DEPRECATED - use libraries instead)
 func (h *AuthHandler) DeleteEbookFolder(c echo.Context) error {
-	userID := c.Get("user_id").(string)
+	return c.JSON(http.StatusGone, map[string]string{"error": "Ebook folders are deprecated. Please use library system instead."})
-	userUUID, err := uuid.Parse(userID)
-	if err != nil {
-		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid user id"})
-	}
-
-	var req DeleteEbookFolderRequest
-	if err := c.Bind(&req); err != nil {
-		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid request"})
-	}
-	if err := c.Validate(&req); err != nil {
-		return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
-	}
-
-	// Normalize the folder path before deletion
-	normalizedPath := normalizePath(req.FolderPath)
-
-	// Debug logging - remove in production
-	fmt.Printf("DeleteEbookFolder: original path='%s', normalized path='%s', user_id='%s'\n",
-		req.FolderPath, normalizedPath, userID)
-
-	deletedFolder, err := h.db.DeleteUserEbookFolder(c.Request().Context(), database.DeleteUserEbookFolderParams{
-		UserID:     pgtype.UUID{Bytes: userUUID, Valid: true},
-		FolderPath: normalizedPath,
-	})
-	if err != nil {
-		fmt.Printf("DeleteEbookFolder failed: %v\n", err)
-		if err == pgx.ErrNoRows {
-			return c.JSON(http.StatusNotFound, map[string]string{"error": "ebook folder not found"})
-		}
-		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
-	}
-
-	fmt.Printf("DeleteEbookFolder succeeded: deleted folder with path '%s'\n", deletedFolder.FolderPath)
-	return c.JSON(http.StatusOK, map[string]string{"message": "ebook folder deleted successfully"})
 }
 
 type UpdateThemeRequest struct {