Require valid campaign save for continue

scripts/verify-campaign-save-normalization.mjs

@@ -30,6 +30,7 @@ try {
     applyCampBondExp,
     applyCampVisitReward,
     getCampaignState,
+    hasCampaignSave,
     loadCampaignState,
     normalizeCampaignSortieItemAssignments,
     resetCampaignState,
@@ -660,6 +661,7 @@ try {
   storage.set(campaignStorageKey, JSON.stringify({ version: 99, step: 'sixty-sixth-camp' }));
   const unsupported = loadCampaignState();
   assert(unsupported.step === 'new', `Expected unsupported future save version to be ignored: ${JSON.stringify(unsupported)}`);
+  assert(!hasCampaignSave(), 'Expected unsupported base save without valid slots to be ignored by hasCampaignSave');
 
   storage.clear();
   storage.set(campaignStorageKey, JSON.stringify({ version: 99, step: 'sixty-sixth-camp' }));
@@ -673,6 +675,7 @@ try {
       gold: 260
     })
   );
+  assert(hasCampaignSave(), 'Expected valid slotted save fallback to be visible to hasCampaignSave');
   const fallback = loadCampaignState();
   assert(fallback.step === 'second-camp' && fallback.activeSaveSlot === 2, `Expected valid slotted save fallback: ${JSON.stringify(fallback)}`);