fix: replace invalid new(expression) calls with proper pointer allocation

Go's new() builtin takes a type and allocates a zero value — it cannot
wrap an expression. All instances of new(someExpression) were compile
errors. Replace each with a local variable assignment and address-of
operator.

Affected files:
- handlers/koreader.go: progress field pointers (Chapter, Page, etc.)
- handlers/kobo.go: pagesRemaining pointer
- handlers/queue.go: uuidPtrToString and timestamptzPtrToString helpers
- router/reader.go: bookmark pageNumber and chapterNumber pointers
- services/media_scanner.go: validation error message pointers
- services/worker.go: StartedAt and CompletedAt timestamps
- sync/offline.go: GetDeviceStatus return pointer
- tests/device_test.go: SyncEnabled and SyncFrequencyMinutes pointers

internal/handlers/kobo.go

@@ -303,7 +303,8 @@ func (h *KoboHandler) Initialization(c *echo.Context) error {
 				lastModified = progress.LastReadAt.Time.Format(time.RFC3339)
 			}
 			if progress.TotalPages.Valid && progress.CurrentPage.Valid {
-				pagesRemaining = new(int(progress.TotalPages.Int32 - progress.CurrentPage.Int32))
+				remaining := int(progress.TotalPages.Int32 - progress.CurrentPage.Int32)
+				pagesRemaining = &remaining
 			}
 		}
 

internal/handlers/koreader.go

@@ -602,19 +602,24 @@ func (h *KOReaderHandler) GetMetadata(c *echo.Context) error {
 		progressData.Epubcfi = &progress.Epubcfi.String
 	}
 	if progress.Chapter.Valid {
-		progressData.Chapter = new(int(progress.Chapter.Int32))
+		progress := int(progress.Chapter.Int32)
+		progressData.Chapter = &progress
 	}
 	if progress.ChapterProgress.Valid {
-		progressData.ChapterProgress = new(progress.ChapterProgress.Float64)
+		progress := progress.ChapterProgress.Float64
+		progressData.ChapterProgress = &progress
 	}
 	if progress.CharacterOffset.Valid {
-		progressData.Character = new(progress.CharacterOffset.Int64)
+		progress := progress.CharacterOffset.Int64
+		progressData.Character = &progress
 	}
 	if progress.CurrentPage.Valid {
-		progressData.Page = new(int(progress.CurrentPage.Int32))
+		progress := int(progress.CurrentPage.Int32)
+		progressData.Page = &progress
 	}
 	if progress.TotalPages.Valid {
-		progressData.TotalPages = new(int(progress.TotalPages.Int32))
+		progress := int(progress.TotalPages.Int32)
+		progressData.TotalPages = &progress
 	}
 
 	annotations, err := h.db.GetAnnotationsForBook(c.Request().Context(), database.GetAnnotationsForBookParams{
@@ -694,7 +699,8 @@ func (h *KOReaderHandler) GetLibrary(c *echo.Context) error {
 		if err == nil {
 			percentRead = progress.Percentage.Float64
 			if progress.TotalPages.Valid && progress.CurrentPage.Valid {
-				pagesRemaining = new(int(progress.TotalPages.Int32 - progress.CurrentPage.Int32))
+				pages := int(progress.TotalPages.Int32 - progress.CurrentPage.Int32)
+				pagesRemaining = &pages
 			}
 			if progress.LastReadAt.Valid {
 				lastModified = progress.LastReadAt.Time.Format(time.RFC3339)

internal/handlers/queue.go

@@ -310,7 +310,8 @@ func uuidPtrToString(u pgtype.UUID) *string {
 	if !u.Valid {
 		return nil
 	}
-	return new(uuid.UUID(u.Bytes).String())
+	s := uuid.UUID(u.Bytes).String()
+	return &s
 }
 
 func textPtrToString(t pgtype.Text) *string {
@@ -324,5 +325,6 @@ func timestamptzPtrToString(t pgtype.Timestamptz) *string {
 	if !t.Valid {
 		return nil
 	}
-	return new(t.Time.Format("2006-01-02T15:04:05Z07:00"))
+	timeFormat := t.Time.Format("2006-01-02T15:04:05Z07:00")
+	return &timeFormat
 }

internal/services/media_scanner.go

@@ -1320,12 +1320,13 @@ func (s *MediaScanner) ValidateMediaItemForLibrary(
 		// Must be fixed-layout or comic archive
 		if mediaItem.FormatGroup != "fixed_layout" &&
 			mediaItem.FormatGroup != "comic_archive" {
-			return new(fmt.Sprintf(
+			str := fmt.Sprintf(
 				"EPUB file '%s' is reflowable (text-based), not fixed-layout (image-based). "+
 					"Manga library only accepts fixed-layout EPUBs, CBZ, CBR, or image files. "+
 					"Consider moving this file to an ebooks library.",
 				mediaItem.Title,
-			))
+			)
+			return &str
 		}
 
 		// Set manga-specific flags for fixed-layout EPUBs
@@ -1350,11 +1351,12 @@ func (s *MediaScanner) ValidateMediaItemForLibrary(
 		// Accept comic archives and fixed-layout
 		if mediaItem.FormatGroup != "comic_archive" &&
 			mediaItem.FormatGroup != "fixed_layout" {
-			return new(fmt.Sprintf(
+			str := fmt.Sprintf(
 				"File '%s' is not a comic archive format. "+
 					"Comics library only accepts CBZ, CBR, CB7, CBT, PDF, or fixed-layout EPUBs.",
 				mediaItem.Title,
-			))
+			)
+			return &str
 		}
 	}
 
@@ -1363,11 +1365,12 @@ func (s *MediaScanner) ValidateMediaItemForLibrary(
 		// Flag manga for potential reorganization (info level)
 		if mediaItem.FormatGroup == "fixed_layout" &&
 			(!mediaItem.MangaType.Valid || mediaItem.MangaType.String == "yes" || mediaItem.MangaType.String == "yes_and_right_to_left") {
-			return new(fmt.Sprintf(
+			str := fmt.Sprintf(
 				"File '%s' appears to be manga (fixed-layout with images). "+
 					"Consider moving to a manga or comics library for better organization.",
 				mediaItem.Title,
-			))
+			)
+			return &str
 		}
 	}
 

internal/services/worker.go

@@ -221,7 +221,8 @@ func (w *Worker) processJob(job *Job) {
 	}
 	w.mu.Unlock()
 
-	job.StartedAt = new(time.Now())
+	started := time.Now()
+	job.StartedAt = &started
 
 	w.mu.Lock()
 	if result, exists := w.results[job.ID]; exists {
@@ -253,7 +254,8 @@ func (w *Worker) processJob(job *Job) {
 		err = fmt.Errorf("unknown job type: %s", job.Type)
 	}
 
-	job.CompletedAt = new(time.Now())
+	completed := time.Now()
+	job.CompletedAt = &completed
 	job.Error = err
 	job.Result = result
 

internal/sync/offline.go

@@ -226,7 +226,8 @@ func (d *OfflineDetector) GetDeviceStatus(ctx context.Context, deviceID pgtype.U
 		return nil, err
 	}
 
-	return new(d.getDeviceStatus(device)), nil
+	deviceStatus := d.getDeviceStatus(device)
+	return &deviceStatus, nil
 }
 
 func (d *OfflineDetector) ListOfflineDevices(ctx context.Context) ([]DeviceOnlineStatus, error) {