Antigravity SDK 0.1.6

[Improvements] Local model connectivity: Introduced LiteRTAgentConfig and LiteRTConnectionStrategy for LiteRT-LM (supporting local Gemma execution), LocalOpenAIAgentConfig and LocalOpenAIConnectionStrategy for OpenAI-compatible APIs (supporting Ollama and LM Studio), and a background loopback HTTP translation server.

[Improvements] Multimodal tool outputs: Enabled custom tools to return media assets (Image, Document, Audio, Video) directly using a single tool response without needing separate follow-up turns (supplemental_media).

[Improvements] Built-in web fetch tool: Integrated the read_url_content tool end-to-end for fetching structured web content natively with the ReadUrlContentResult Pydantic model.

[Improvements] MCP string prefix modernization: Decoupled tool calls and safety policy engines from legacy "mcp_" string synthesis, resolving name mismatch issues by utilizing explicit server_name attributes in tool evaluation.

[Fixes] Python 3.14 compatibility: Resolved namespace class conflicts and typing normalization issues in agent.py and public_api_test.py under Python 3.14 deferred annotations evaluation.

[Fixes] Vertex validation errors: Cleared a misleading reference to API keys in VertexEndpoint validation error messages, limiting fields to project and location.

[Fixes] OTel trace warnings: Resolved detached contextvars warnings and set-status race conditions by removing use_span context managers from Turn/Session hooks and checking span recording readiness.

[Fixes] Exception wrapping mapping: Fixed agent_middleware integration check failures by making the example check for error message substrings instead of strict exception types.