fix(storage): resolve persistence restart bug across all storage adapters

Critical bug fix that restores data persistence after application restart for all storage adapters (GCS, S3, OPFS, FileSystem).

**Root Cause:**
Storage adapters were loading entity counts from _system/counts.json but not returning totalCount in pagination methods, causing rebuildIndexesIfNeeded() to see undefined and incorrectly assume no data existed.

**Changes:**
- GCS Storage: Return totalCount in getNodesWithPagination() and getVerbsWithPagination()
- S3 Storage: Call initializeCounts() in init() and return totalCount in pagination methods
- OPFS Storage: Call initializeCounts() in init() to load pre-calculated counts
- BaseStorage: Add defensive validation to prevent future adapters from missing totalCount

**Impact:**
- Production deployments now work correctly (Cloud Run, AWS, Kubernetes)
- Data persists correctly across container restarts
- Serverless scale-to-zero deployments now functional
- All storage adapters use O(1) pre-calculated counts (scales to millions of entities)

**Testing:**
- Build passes with no TypeScript errors
- All existing tests pass
- Defensive validation ensures future storage adapters won't have this bug

Fixes critical production issue affecting all persistent storage deployments.

src/storage/baseStorage.ts

@@ -508,9 +508,21 @@ export abstract class BaseStorage extends BaseStorageAdapter {
         // This prevents pagination bugs from causing infinite loops
         const safeHasMore = items.length > 0 ? result.hasMore : false
 
+        // VALIDATION: Ensure adapter returns totalCount (prevents restart bugs)
+        // If adapter forgets to return totalCount, log warning and use pre-calculated count
+        let finalTotalCount = result.totalCount || totalCount
+        if (result.totalCount === undefined && this.totalNounCount > 0) {
+          console.warn(
+            `⚠️  Storage adapter missing totalCount in getNounsWithPagination result! ` +
+            `Using pre-calculated count (${this.totalNounCount}) as fallback. ` +
+            `Please ensure your storage adapter returns totalCount: this.totalNounCount`
+          )
+          finalTotalCount = this.totalNounCount
+        }
+
         return {
           items,
-          totalCount: result.totalCount || totalCount,
+          totalCount: finalTotalCount,
           hasMore: safeHasMore,
           nextCursor: result.nextCursor
         }
@@ -705,9 +717,21 @@ export abstract class BaseStorage extends BaseStorageAdapter {
         // This prevents pagination bugs from causing infinite loops
         const safeHasMore = items.length > 0 ? result.hasMore : false
 
+        // VALIDATION: Ensure adapter returns totalCount (prevents restart bugs)
+        // If adapter forgets to return totalCount, log warning and use pre-calculated count
+        let finalTotalCount = result.totalCount || totalCount
+        if (result.totalCount === undefined && this.totalVerbCount > 0) {
+          console.warn(
+            `⚠️  Storage adapter missing totalCount in getVerbsWithPagination result! ` +
+            `Using pre-calculated count (${this.totalVerbCount}) as fallback. ` +
+            `Please ensure your storage adapter returns totalCount: this.totalVerbCount`
+          )
+          finalTotalCount = this.totalVerbCount
+        }
+
         return {
           items,
-          totalCount: result.totalCount || totalCount,
+          totalCount: finalTotalCount,
           hasMore: safeHasMore,
           nextCursor: result.nextCursor
         }