Add docstring to Repeated class documenting independent parameters

[Copilot]

Addresses review feedback from #1 requesting documentation for the Repeated class's parameter behavior.

Changes

• Added docstring to Repeated class clarifying that each repetition has independently initialized parameters (not shared weights)

class Repeated(LayerBase):
    """Applies the same layer n times sequentially.

    Each repetition has independent, separately initialized parameters.
    This is typical for transformer blocks where each layer has its own weights.
    """

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