chore(ci): update workflow runs-on label to ubuntu-latest

.gitea/workflows/auto_backup_schedule.yml

@@ -8,7 +8,7 @@ on:
 
 jobs:
   daily-backup:
-    runs-on: act-runner
+    runs-on: ubuntu-latest
     name: Daily Backup
 
     steps:
@@ -41,7 +41,7 @@ jobs:
           ls -lh backups/ | tail -5
 
   weekly-full-backup:
-    runs-on: act-runner
+    runs-on: ubuntu-latest
     name: Weekly Full Backup
 
     # 매주 월요일 1:00 UTC
@@ -85,7 +85,7 @@ jobs:
           df -h | grep -E "Filesystem|data"
 
   backup-health-check:
-    runs-on: act-runner
+    runs-on: ubuntu-latest
     name: Backup Health Check
 
     # 매일 12:00 UTC
@@ -127,7 +127,7 @@ jobs:
           du -sh backups/ | awk '{print "Total size: " $1}'
 
   test-recovery:
-    runs-on: act-runner
+    runs-on: ubuntu-latest
     name: Monthly Recovery Test
 
     # 매월 1일 2:00 UTC