fix: resume campaign progress safely

scripts/verify-story-asset-data.mjs

@@ -40,6 +40,7 @@ try {
   const errors = [];
   const storySources = collectStorySources(scenarioModule, battleScenarios);
   const uniquePageIds = new Set();
+  const firstSourceByPageId = new Map();
   const usedBackgroundKeys = new Set();
   const selectedBackgroundKeys = new Set();
   const selectedBackgroundUrlsByBase = new Map();
@@ -93,6 +94,17 @@ try {
 
     pages.forEach((page, index) => {
       pageCount += 1;
+      const firstSource = firstSourceByPageId.get(page.id);
+      if (firstSource) {
+        errors.push(
+          `story page id global uniqueness: duplicate "${page.id}" at ${source}[${index}], first used at ${firstSource}`
+        );
+      } else {
+        firstSourceByPageId.set(
+          page.id,
+          `${source}[${index}]`
+        );
+      }
       uniquePageIds.add(page.id);
       validateStoryPage({
         errors,
@@ -127,6 +139,11 @@ try {
   if (pageCount !== expectedStoryPageCount) {
     errors.push(`story page selection coverage: expected ${expectedStoryPageCount} pages, received ${pageCount}`);
   }
+  if (uniquePageIds.size !== pageCount) {
+    errors.push(
+      `story page id global uniqueness: expected ${pageCount} unique ids, received ${uniquePageIds.size}`
+    );
+  }
   if (portraitSelectionMetrics.pages !== pageCount) {
     errors.push(
       `story portrait selection coverage: checked ${portraitSelectionMetrics.pages}/${pageCount} pages`