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/db/dbHelper.go

@@ -53,21 +53,6 @@ func CloseDb() {
 	Dbpool.Close()
 }
 
-func Testf() {
-	rows, dbErr := Dbpool.Query(Ctx, "select game_name from game")
-	if dbErr != nil {
-		logging.GetLogger().Fatal("Query failed", zap.String("error", dbErr.Error()))
-	}
-	for rows.Next() {
-		var gameName string
-		dbErr = rows.Scan(&gameName)
-		if dbErr != nil {
-			logging.GetLogger().Error("Row scan failed", zap.String("error", dbErr.Error()))
-		}
-		logging.GetLogger().Debug("Game found", zap.String("name", gameName))
-	}
-}
-
 func ResetGameIdSeq() {
 	_, err := Dbpool.Query(Ctx, "SELECT setval('game_id_seq', (SELECT MAX(id) FROM game)+1);")
 	if err != nil {