feat: add short memory to agent

[imotai]

PR-Codex overview

This PR focuses on adding a new feature to the agent SDK for creating and managing sessions. It also includes updates to the memory module and tests.

Detailed summary

• Added AgentSyncSession and AgentAsyncSession classes to the agent SDK for session management.
• Modified the prompt method in AgentBaseSDK to accept a context_id parameter for session-based prompts.
• Updated the agent_memory_to_context function in the memory module to handle new prompt parameters.
• Added new tests for the updated functionality.

The following files were skipped due to too many changes: memory/src/og_memory/memory.py, chat/src/og_terminal/terminal_chat.py, agent/tests/openai_agent_tests.py, agent/src/og_agent/prompt.py, agent/src/og_agent/llama_agent.py, agent/src/og_agent/openai_agent.py, agent/src/og_agent/base_agent.py

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