Implement comprehensive Strands Agents configuration JSON schema

- Single comprehensive schema file covering all configuration types
- Validates agent, graph, swarm, and tools configurations
- Enforces types without restrictive min/max constraints
- Supports nested configurations (agents-as-tools, graphs-as-tools, swarms-as-tools)
- Handles complex conditions, structured output, and all ConfigLoader features
- Provides sensible defaults for optional fields
- Tested against all 9 example configurations with 100% success rate

Schema features:
- Top-level key validation (agent:, graph:, swarm:, tools:)
- Comprehensive type enforcement
- Flexible validation with additionalProperties
- Support for null values where appropriate
- Nested tool configurations
- Graph edge conditions with multiple types
- Swarm agent configurations
- Structured output validation

Ready for IDE integration and external validation tools

Author: vawsgit