Package agent_arena_sdk for pip install (pyproject.toml)

[justinmadison]

Problem

The starters import from agent_arena_sdk import AgentArena, Observation, Decision but there's no proper Python package configuration. Currently this works because starters manipulate sys.path or are run from specific directories.

For the target user experience — clone a starter, pip install, run — the SDK needs to be a proper installable package.

Proposed Solution

Add a pyproject.toml to the SDK package so users can install it:

# From the repo root
pip install -e python/sdk/

# Or from a starter
pip install agent-arena-sdk  # if published to PyPI eventually

Package Structure

python/sdk/
├── pyproject.toml          # Package metadata, dependencies
├── agent_arena_sdk/
│   ├── __init__.py         # Public API exports
│   ├── arena.py            # AgentArena class
│   ├── schemas/            # Observation, Decision, ToolSchema
│   ├── server/             # MinimalIPCServer
│   └── adapters/           # Framework adapter base (from #74)
└── README.md               # Package docs

Starter requirements.txt

agent-arena-sdk             # Core SDK
# Framework-specific:
langchain-core>=0.3         # Only in langchain starter
anthropic>=0.40             # Only in claude-sdk starter

Acceptance Criteria

• pyproject.toml with proper metadata, version, and dependencies
• pip install -e python/sdk/ works from repo root
• All starters work after installing the SDK package
• Public API is clean: from agent_arena_sdk import AgentArena, Observation, Decision
• Framework-specific dependencies are NOT in the core SDK (they go in starter requirements.txt)
• Version pinned to match project version in project.godot

Estimated Effort

Half day

Dependencies

• Should follow SDK consolidation issue (single API to package)
• Blocks all starters having a clean install experience