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>

docs/PERFORMANCE.md

@@ -148,7 +148,7 @@ class NaturalLanguageProcessor {
   private fieldEmbeddings = new Map<string, Vector>()
   
   // Type-field affinity for intelligent prioritization
-  async getFieldsForType(nounType: string) {
+  async getFieldsForType(nounType: NounType) {
     return this.brain.getFieldsForType(nounType)  // Real data patterns
   }
 }