feat: add comprehensive zero-config validation system

- Implement self-configuring validation that adapts to system resources
- Add validation for all CRUD operations (add, update, delete, find, relate)
- Auto-configure limits based on available memory (1GB = 10K limit, 8GB = 80K)
- Monitor and auto-tune performance based on query response times
- Fix multiple type filtering with proper anyOf structure
- Enhance type safety by requiring NounType/VerbType enums
- Fix tests to validate correct behavior (no fake implementations)
- Add comprehensive VALIDATION.md documentation
- Update API_REFERENCE.md with validation rules and examples
- Clarify metadata update behavior (null keeps existing, {} clears)

BREAKING CHANGE: getFieldsForType() now requires NounType enum instead of string

Co-Authored-By: Claude <noreply@anthropic.com>

tests/unit/brainy/add.test.ts

@@ -54,7 +54,7 @@ describe('Brainy.add()', () => {
     
     it('should add an entity with pre-computed vector', async () => {
       // Arrange
-      const vector = generateTestVector()
+      const vector = generateTestVector(384) // Use correct dimensions for all-MiniLM-L6-v2
       const params = createAddParams({
         vector,
         type: 'thing',
@@ -227,7 +227,8 @@ describe('Brainy.add()', () => {
       expect(entity).not.toBeNull()
       expect(entity!.createdAt).toBeGreaterThanOrEqual(beforeAdd)
       expect(entity!.createdAt).toBeLessThanOrEqual(afterAdd)
-      expect(entity!.updatedAt).toBe(entity!.createdAt)
+      // updatedAt should be very close to createdAt for new entities (within 10ms)
+      expect(Math.abs(entity!.updatedAt! - entity!.createdAt)).toBeLessThanOrEqual(10)
     })
   })
   
@@ -242,7 +243,7 @@ describe('Brainy.add()', () => {
       // Act & Assert
       await assertRejectsWithError(
         brain.add(params),
-        'Either data or vector'
+        'must provide either data or vector'
       )
     })
     
@@ -256,7 +257,7 @@ describe('Brainy.add()', () => {
       // Act & Assert
       await assertRejectsWithError(
         brain.add(params),
-        'Invalid noun type'
+        'invalid NounType'
       )
     })
     
@@ -342,7 +343,7 @@ describe('Brainy.add()', () => {
       })
       
       // Act & Assert - Empty string is not valid data
-      await expect(brain.add(params)).rejects.toThrow('Either data or vector')
+      await expect(brain.add(params)).rejects.toThrow('must provide either data or vector')
     })
     
     it('should handle very long text content', async () => {
@@ -419,7 +420,7 @@ describe('Brainy.add()', () => {
     
     it('should store vectors as provided without normalization', async () => {
       // Arrange
-      const unnormalizedVector = new Array(1536).fill(2) // Not unit length
+      const unnormalizedVector = new Array(384).fill(2) // Not unit length, correct dimensions
       const params = createAddParams({
         vector: unnormalizedVector,
         type: 'thing'