Refactor handlers and update changelog for 5.0.0-Beta

- Split IndexHandler into HealthHandler, VersionHandler, and CharacterHandler
- Rename index.go to version.go in backend
- Change VersionData.Changelog from string to []string
- Add changelog entries for issues #16-#23
- Remove TestDB function and related code
- Fix import ordering in several files

Closes #21, #22
References #16, #17, #18, #19, #20, #23

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

internal/backend/characters.go

@@ -4,8 +4,8 @@ import (
 	"os"
 	"strings"
 
-	"music-server/internal/logging"
 	"go.uber.org/zap"
+	"music-server/internal/logging"
 )
 
 func GetCharacterList() []string {
@@ -30,10 +30,10 @@ func GetCharacterList() []string {
 
 func GetCharacter(character string) string {
 	charactersPath := os.Getenv("CHARACTERS_PATH")
-	logging.GetLogger().Debug("Getting character", zap.String("character", character), zap.String("path", charactersPath))
 	// Clean the path - remove trailing slashes and then add one for consistency
 	charactersPath = strings.TrimSuffix(charactersPath, "/")
 	charactersPath += "/"
+	logging.GetLogger().Debug("Getting character", zap.String("character", character), zap.String("path", charactersPath+character))
 	return charactersPath + character
 }