feat(agents): add declarative OCG configuration

[NicholasDCole]

Summary

This replaces the earlier client-managed OCG memory approach with a minimal, declarative integration.

Users enable OCG directly on an agent:

Agent(
    ...,
    ocg=OcgConfig(
        url=OCG_INSTANCE_URL,
        credential="OCG_PUBLIC_KEY",
    ),
)

The SDK serializes only the server-owned longTermMemory metadata:

• normalized OCG URL
• Conductor credential/secret name (never a raw API key)
• generated ownership identity: conductor-agent:<agent name>
• optional user identity

Conductor dynamically discovers the OCG MCP function catalog and exports raw terminal runs through its completion listener. The Python SDK performs no local OCG retrieval, summarization, feedback handling, or token resolution.

Changes

• add and publicly export OcgConfig
• add optional ocg configuration to Agent
• serialize OCG metadata independently of conversation or semantic memory
• document the longTermMemory wire contract in the AgentConfig JSON Schema
• remove the SDK-defined OCG query/graph/memory tools and their examples/tests
• add focused validation and serialization unit tests

Test results

107 passed in 0.39s

Test command:

pytest -q tests/unit/ai/test_ocg_config.py tests/unit/ai/test_config_serializer.py tests/unit/ai/test_agent.py tests/unit/ai/test_agent_schema_contract.py tests/unit/ai/credentials/test_public_api.py

Supersedes #423.