fix(mcp): validate episode types before queueing

[vismaytiwari]

Addresses #1164

Summary

This validates MCP episode type configuration before an episode is added to the background queue.

Previously, add_memory could return a queued-success response even when Graphiti.add_episode would immediately reject the configured entity types. The queue worker then logged the failure later, so callers only saw success while the episode was never processed.

This reuses Graphiti's existing entity-type and excluded-entity-type validators in QueueService.add_episode, before creating the background task. Invalid reserved fields such as DataObject.attributes now fail before queueing, so the MCP tool returns an error instead of a false success message.

Validation

• Reproduced the current behavior locally: QueueService.add_episode returned a queue position, then the worker logged attributes cannot be used as an attribute for DataObject as it is a protected attribute name.
• Verified after the change that the same case raises before queue creation and the Graphiti client is not called.
• Verified add_memory now returns an error response for that case and does not create a queue.
• uv run pytest tests/test_core_parity.py -q from mcp_server: 28 passed.
• uv run ruff check src/services/queue_service.py tests/test_core_parity.py: passed.
• uv run ruff format --check src/services/queue_service.py tests/test_core_parity.py: passed.
• uv run pyright src/services/queue_service.py: 0 errors.

Note: I also tried MCP-wide uv run pyright src tests, but it currently reports existing unrelated MCP test/import typing issues, so I kept the pyright check scoped to the changed service file.

[zep-cla-assistant]

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[vismaytiwari]

I have read the CLA Document and I hereby sign the CLA behalf of myself , e-mail: vismay.t@gmail.com

[vismaytiwari]

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