fix: Incomplete Agent Trust Validation in ConfigValidator

[Aditya8369]

✅ Implementation Complete

1. AgentTrustConfig TypedDict ✓

• Created in types.py
• Defines required and optional trust configuration fields:
  • required_verification_level (10 valid levels)
  • max_agent_hierarchy_depth (prevents infinite nesting)
  • allowed_origins (domain restriction with wildcard support)
  • identity_provider, trust_verification_required, certificate_required
  • Custom metadata for deployment needs

2. ConfigValidator Updates ✓

• _process_complex_fields(): Now validates agent_trust against the schema
• _validate_agent_trust_config(): New comprehensive validation method with:
  • Trust level validation (admin, analyst, auditor, editor, guest, manager, operator, super_admin, support, viewer)
  • Hierarchy depth validation (must be ≥ 1)
  • Origin URL format validation with wildcard support
  • Boolean and metadata type checking

3. Comprehensive Unit Tests ✓

• 40+ test methods covering all validation scenarios
• Located in test_config_validator.py
• Tests for valid/invalid configs, all trust levels, edge cases

4. Sample Configuration ✓

• Created test_config_with_trust.json
• Demonstrates all fields in a realistic agent configuration
• Successfully validates with full integration testing

5. Complete Documentation ✓

• 350+ line comprehensive AGENT_TRUST.md:
  • Field-by-field documentation with examples
  • 5 complete example configs (development, production, high-security, multi-tenant)
  • Best practices and validation error scenarios
  • Links to related documentation

6. Updated README ✓

• Added "Agent Trust Configuration" to README.md features table
• Links to new AGENT_TRUST.md documentation

7. Bug Fix ✓

• Fixed Pydantic 2.x compatibility issue in types.py (removed deprecated rebuild() calls)

Test Results

✅ 8/8 scenario tests passed
✅ 10/10 trust level validations passed  
✅ Sample config validation passed
✅ Full integration tests passed

Key Features

• 🛡️ Schema Enforcement - Strict type checking prevents misconfigurations
• 🔒 Origin Control - Restrict agent invocation to specific domains
• 🎯 Hierarchy Protection - Prevents dangerous nesting depths
• ✅ Comprehensive Validation - Clear error messages for configuration issues
• 🔐 Production Ready - Certificate support and verification options
• 📚 Well Documented - Complete guides and examples

closes #382

[Aditya8369]

@raahulrahl please consider this PR fixing the incomplete validations