feat(agent-memory): add create_checkpointer() factory with TTL support for LangGraph agents

[santosh-nallur]

Description

Adds a create_checkpointer() factory in the agent_memory module that returns a LangGraph BaseCheckpointSaver appropriate for the current environment. Enables LoB teams (e.g. IBD) to integrate LangGraph agent short-term memory without coupling their agent code to a specific checkpointer implementation.

What ships in this PR:

• src/sap_cloud_sdk/agent_memory/factory/langgraph_checkpoint.py — create_checkpointer() factory returning InMemorySaver (no TTL) or TimedInMemorySaver (with TTL)
• src/sap_cloud_sdk/agent_memory/factory/_timed_memory.py — TimedInMemorySaver extending InMemorySaver with a daemon background sweep thread for TTL-based thread eviction
• src/sap_cloud_sdk/agent_memory/factory/__init__.py — factory subpackage
• tests/agent_memory/unit/test_langgraph_checkpointer.py — factory unit tests
• tests/agent_memory/unit/test_timed_memory.py — TimedInMemorySaver unit tests
• src/sap_cloud_sdk/agent_memory/user-guide.md — LangGraph Checkpointer section

usage:

from sap_cloud_sdk.agent_memory.factory.langgraph_checkpoint import create_checkpointer

# Without TTL
checkpointer = create_checkpointer()

# With TTL — evicts threads inactive for 1 hour
checkpointer = create_checkpointer(ttl_seconds=3600)

app = workflow.compile(checkpointer=checkpointer)

TimedInMemorySaver design:

• Tracks last-active time per thread via _last_active dict updated in put() / aput()
• Daemon sweep thread runs every 60 seconds and evicts threads exceeding ttl_seconds of inactivity
• Sweep is fully decoupled from the read/write path — hot path adds one dict write only
• ttl_seconds parameter stable for Phase 2 when HanaAgentMemorySaver ships

Type of Change

• New feature (non-breaking change that adds functionality)
• Documentation update

How to Test

# Run new unit tests
uv run pytest tests/agent_memory/unit/test_langgraph_checkpointer.py -v
uv run pytest tests/agent_memory/unit/test_timed_memory.py -v

# Run full unit suite
uv run pytest tests/agent_memory/unit/ -v

Checklist

• I have read the Contributing Guidelines
• I have verified that my changes solve the issue
• I have added/updated automated tests to cover my changes
• All tests pass locally
• I have verified that my code follows the Code Guidelines
• I have updated documentation (if applicable)
• I have added type hints for all public APIs
• My code does not contain sensitive information (credentials, tokens, etc.)
• I have followed Conventional Commits for commit messages

Breaking Changes

None. The factory subpackage is additive. No existing public API is changed.

Additional Notes

• TimedInMemorySaver is a temporary home in the SDK factory subpackage. It will migrate to langgraph-checkpoint-sap-agent-memory (the separate checkpoint library in Phase 2 — no code change required for factory consumers.
• The ttl_seconds parameter is accepted on create_checkpointer() regardless of which backend is active, ensuring interface stability for Phase 2.
• Phase 2 factory (when HanaAgentMemorySaver ships) will detect the HANA binding at runtime and return it automatically

[santosh-nallur]

Thanks @NicoleMGomes , @cassiofariasmachado, I realised that the new TTL field for checkpointer could be a configuration via decorators. Rather than introducing a new checkpointer specific decorator, reused the existing agent_config instead. Added an example in the user-guide.md
Hope this is fine ?

[cassiofariasmachado]

Please bump the version to 0.33.0

Suggested change

	version = "0.32.0"
	version = "0.33.0"