v0.4.4 - Proper session lifecycle management

What's Changed

Fix: Unclosed client sessions

Added proper lifecycle management to ClaudeAcpAgent and ClaudeClient to prevent unclosed subprocess connections (and associated aiohttp session warnings).

New methods:

• ClaudeAcpAgent.close() / close_session(session_id) — properly disconnects ClaudeSDKClient instances
• ClaudeClient.close() — delegates to agent cleanup
• Both now support async with context manager for automatic cleanup

Usage:

# Recommended: async context manager
async with ClaudeClient(cwd=".") as client:
    response = await client.query("Hello")

# Or manual cleanup
client = ClaudeClient(cwd=".")
try:
    response = await client.query("Hello")
finally:
    await client.close()

Also:

• run() entry point now ensures agent.close() on shutdown via try/finally
• Updated README examples to use async with pattern
• Added unit tests for lifecycle methods