Release v0.1.0: SubAgent Library and Comprehensive Documentation

Major Features:
- SubAgent library for simplified agent development (75% code reduction)
- Comprehensive godoc documentation across all internal packages
- Dynamic agent discovery with Cortex orchestration
- A2A-compliant agent card generation

Library Documentation:
- internal/subagent: Complete package documentation with examples
- internal/agenthub: Broker and client infrastructure documentation
- internal/observability: Tracing, metrics, and logging guide
- internal/config: Configuration management documentation

Improvements:
- Automatic observability wrapping for all task handlers
- Graceful shutdown and lifecycle management
- Health check endpoints for all services
- Enhanced A2A protocol compliance

Bug Fixes:
- Fixed echo_agent panic on context cancellation
- Fixed incomplete AgentCard generation
- Fixed infinite loop in Cortex task orchestration
- Fixed context cancellation in async event delivery

Breaking Changes: None

Documentation: 1,311 lines of godoc added
Examples: Echo agent reduced from 211 to 82 lines

For details, see: docs/content/en/docs/howto/agents/create_agent_with_cortex.md

Release v0.0.2: Agent2Agent (A2A) Protocol Compliance

This release implements complete Agent2Agent (A2A) protocol v0.2.9 compliance while maintaining Event-Driven Architecture scalability benefits.

Key Features:
- Full A2A protocol compliance with standardized message structures
- Hybrid EDA+A2A architecture for scalability and interoperability
- Complete documentation overhaul for A2A compliance
- High-level A2A client abstractions for easier integration
- Enhanced observability with OpenTelemetry integration

Breaking Changes:
- AgentHub service replaces legacy EventBus
- A2A message structures replace custom formats
- Legacy task handlers need migration to A2A format

For full details, see CHANGELOG.md

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