Add py.typed file

[danielchalef]

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:rocket:	This description was created by Ellipsis for commit 2e3d97acfd78948d04092c1c58b89c454596ee72

Summary:

Add py.typed file to graphiti_core and update pyproject.toml to include it in the package distribution.

Key points:

• Add graphiti_core/py.typed to indicate the package is typed.
• Update pyproject.toml to include py.typed in the graphiti_core package distribution.

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