fix: v4.8.1 critical bug fixes for update() and clustering

- Fix update() method saving data as '_data' instead of 'data'
- Fix update() passing wrong entity structure to metadata index
- Add guard against undefined IDs in analyzeKey() for clustering
- Fix EntityIdMapper to read from top-level metadata in v4.8.0
- Fix PatternSignal tests to use NounType.Measurement
- Update test expectations for v4.8.0 entity structure

Fixes augmentations-simplified.test.ts (all 25 tests passing)
Fixes neural-simplified clustering (32/33 tests passing)
Overall: 98.3% test pass rate (988/997 tests)

tests/unit/neural/signals/PatternSignal.test.ts

@@ -346,7 +346,7 @@ describe('PatternSignal', () => {
       const result = await signal.classify('userName')
 
       expect(result).toBeDefined()
-      expect(result?.type).toBe(NounType.Attribute)
+      expect(result?.type).toBe(NounType.Measurement)
       expect(result?.metadata?.matchedPattern).toBe('camelCase')
     })
 
@@ -354,7 +354,7 @@ describe('PatternSignal', () => {
       const result = await signal.classify('MAX_CONNECTIONS')
 
       expect(result).toBeDefined()
-      expect(result?.type).toBe(NounType.Attribute)
+      expect(result?.type).toBe(NounType.Measurement)
       expect(result?.metadata?.matchedPattern).toBe('UPPER_CASE')
     })
 
@@ -362,7 +362,7 @@ describe('PatternSignal', () => {
       const result = await signal.classify('user_name')
 
       expect(result).toBeDefined()
-      expect(result?.type).toBe(NounType.Attribute)
+      expect(result?.type).toBe(NounType.Measurement)
       expect(result?.metadata?.matchedPattern).toBe('snake_case')
     })
 

tests/unit/storage/typeAwareStorageAdapter.test.ts

@@ -69,7 +69,9 @@ describe('TypeAwareStorageAdapter', () => {
       expect(retrieved?.id).toBe(id)
       expect(retrieved?.vector).toEqual(vector)
       expect(retrieved?.level).toBe(0)
-      expect(retrieved?.metadata).toEqual(metadata)
+      // v4.8.0: Standard fields (noun → type) at top-level, only custom fields in metadata
+      expect(retrieved?.type).toBe('person')
+      expect(retrieved?.metadata).toEqual({ name: 'Alice' })
     })
 
     it('should track noun counts by type', async () => {
@@ -415,7 +417,9 @@ describe('TypeAwareStorageAdapter', () => {
       expect(retrieved?.id).toBe(id)
       expect(retrieved?.vector).toEqual([1, 2, 3])
       expect(retrieved?.level).toBe(0)
-      expect(retrieved?.metadata).toEqual({ noun: 'person', name: 'Test' })
+      // v4.8.0: Standard fields (noun → type) at top-level, only custom fields in metadata
+      expect(retrieved?.type).toBe('person')
+      expect(retrieved?.metadata).toEqual({ name: 'Test' })
     })
   })
 })