docs: add workspace option documentation

[Bryasxin]

• This PR contains AI-generated code, but I have carefully reviewed it myself. Otherwise, my PR may be closed.

Description

Add workspace option documentation covering package discovery (auto/explicit modes), configuration inheritance, per-package config overrides, filtering with --filter, and the config: false option.

Linked Issues

Additional context

Adds the workspace entry to the docs sidebar under Options.

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commit: 23153ec