Fix Go 1.25 format string errors

## Issue
Go 1.25 has stricter format string checks, causing build failures:
- errors.Wrapf requires ErrorCode as second parameter
- log.Printf requires format string

## Changes
- pkg/store/file/fileStore.go: Added missing errors.StoreError codes (2 locations)
- pkg/store/file/fileStore_test.go: Fixed log.Printf to use format string

## Test Results
✅ pkg/cfg - PASS
✅ pkg/eval - PASS (including fixed certificate tests)
✅ pkg/store/file - PASS
✅ pkg/store/etcd - PASS
❌ pkg/store/mongodb - FAIL (expected: no MongoDB server available)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: William Cai

pkg/store/file/fileStore.go

@@ -145,13 +145,13 @@ func (s *Store) GetPolicyAndRolePolicyCounts() (map[string]*pms.PolicyAndRolePol
 
 		policyCount, err := s.getPolicyCountWithoutLock(srvName)
 		if err != nil {
-			return nil, errors.Wrapf(err, "failed to get policy count for service: %s", srvName)
+			return nil, errors.Wrapf(err, errors.StoreError, "failed to get policy count for service: %s", srvName)
 		}
 		counts.PolicyCount = policyCount
 
 		rolePolicyCount, err := s.getRolePolicyCountWithoutLock(srvName)
 		if err != nil {
-			return nil, errors.Wrapf(err, "failed to get rolePolicy count for service: %s", srvName)
+			return nil, errors.Wrapf(err, errors.StoreError, "failed to get rolePolicy count for service: %s", srvName)
 		}
 		counts.RolePolicyCount = rolePolicyCount
 

pkg/store/file/fileStore_test.go

@@ -59,7 +59,7 @@ func TestWriteReadPolicyStore(t *testing.T) {
 		t.Error("should have 10 services in the store")
 	}
 	for _, service := range psr.Services {
-		log.Printf(service.Name)
+		log.Printf("%s", service.Name)
 	}
 
 }