* Add weierstrass_method for approximating complex roots
- Implements Durand-Kerner (Weierstrass) method for polynomial root finding
- Accepts user-defined polynomial function and degree
- Uses random perturbation of complex roots of unity for initial guesses
- Handles validation, overflow clipping, and includes doctest
* Update weierstrass_method.py
* add more tests
* [pre-commit.ci] auto fixes from pre-commit.com hooks
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* Update weierstrass_method.py
* Update weierstrass_method.py
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