fix: exclude __words__ keyword index from corruption detection and getStats()

The __words__ keyword index stores 50-5000 entries per entity (one per
word), which inflated avg entries/entity well above the corruption
threshold of 100. This caused:

1. validateConsistency() to falsely detect corruption on every startup,
   triggering unnecessary clearAllIndexData() + rebuild() cycles
2. getStats() to log false "Metadata index may be corrupted" warnings
   and report inflated totalEntries/totalIds stats

Both methods now skip __words__ when counting, so stats and health
checks reflect metadata fields only (noun, type, createdAt, etc.).
Keyword search is unaffected since the __words__ field index itself
is not modified.

src/augmentations/intelligentImport/IntelligentImportAugmentation.ts

@@ -35,7 +35,7 @@ export class IntelligentImportAugmentation extends BaseAugmentation {
       enableCSV: true,
       enableExcel: true,
       enablePDF: true,
-      enableImage: true, // v5.2.0: Image handler enabled by default
+      enableImage: true, // Image handler enabled by default
       maxFileSize: 100 * 1024 * 1024, // 100MB default
       enableCache: true,
       cacheTTL: 24 * 60 * 60 * 1000, // 24 hours