chore: checkpoint stable battle and eidolon progression

internal/gameserver/battle_rules.go

@@ -3,7 +3,6 @@ package gameserver
 import (
 	"encoding/json"
 	"fmt"
-	"os"
 	"strings"
 	"sync"
 
@@ -51,7 +50,7 @@ var battleRulesErr error
 
 func loadBattleRules() (*battleRules, error) {
 	battleRulesOnce.Do(func() {
-		raw, err := os.ReadFile("resources/BattleRules.json")
+		raw, err := common.ReadResourceFile("resources/BattleRules.json", "BattleRules.json")
 		if err != nil {
 			battleRulesErr = err
 			return