v0.3.0

What's Changed

• Added static analysis for agent host_context dependencies, including validation that child agents can receive required context from parent agents or datasources.
• Added host_context details to compiled manifests and generated documentation.
• Added capability registry support via contract4agents.registry.json, with validation and drift checks against compiled contracts for tools, hosted tools, agents, output types, prompts, and host context.
• Added run spec evaluation support for host-owned multi-agent runs, including stage output validation and trace-based assertion checks.
• Improved datasource resolution behavior, including clearer handling for missing, ambiguous, cyclic, and denied datasource dependencies.