fix(storage): clean up variable shadowing and dead code (#761)

- Rename `filepath` local var to `dest` in LocalStorage.Upload to avoid
  shadowing the path/filepath package import
- Remove unused detectContentType and overrideContentType functions from
  util.go (no longer needed after ServeFile switched to http.ServeFile)

server/internal/storage/local.go

@@ -80,8 +80,8 @@ func (s *LocalStorage) DeleteKeys(ctx context.Context, keys []string) {
 }
 
 func (s *LocalStorage) Upload(ctx context.Context, key string, data []byte, contentType string, filename string) (string, error) {
-	filepath := filepath.Join(s.uploadDir, key)
-	if err := os.WriteFile(filepath, data, 0644); err != nil {
+	dest := filepath.Join(s.uploadDir, key)
+	if err := os.WriteFile(dest, data, 0644); err != nil {
 		return "", fmt.Errorf("local storage WriteFile: %w", err)
 	}
 

server/internal/storage/util.go

@@ -1,8 +1,6 @@
 package storage
 
 import (
-	"net/http"
-	"path"
 	"strings"
 )
 
@@ -21,34 +19,6 @@ func sanitizeFilename(name string) string {
 	return b.String()
 }
 
-// detectContentType determines the content type for a file.
-// Uses http.DetectContentType as base, with overrides for common extensions.
-func detectContentType(data []byte, filename string) string {
-	contentType := http.DetectContentType(data)
-	ext := strings.ToLower(path.Ext(filename))
-	if ct := overrideContentType(ext); ct != "" {
-		return ct
-	}
-	return contentType
-}
-
-// overrideContentType returns content type overrides for extensions that http.DetectContentType gets wrong.
-func overrideContentType(ext string) string {
-	switch ext {
-	case ".svg":
-		return "image/svg+xml"
-	case ".css":
-		return "text/css"
-	case ".js", ".mjs":
-		return "application/javascript"
-	case ".json":
-		return "application/json"
-	case ".wasm":
-		return "application/wasm"
-	}
-	return ""
-}
-
 // isInlineContentType returns true for media types that browsers should
 // display inline (images, video, audio, PDF). Everything else triggers a
 // download via Content-Disposition: attachment.