Fix: raise ValueError when run_simplex exceeds max iterations

[MeriemBchini]

Summary

run_simplex() previously returned an empty dictionary when the maximum
iteration limit was reached, silently masking convergence failures.

Changes

• Replaced silent return {} with a descriptive ValueError
• Added iteration tracking to improve debugging clarity

Why this matters

Prevents silent failures and allows users to distinguish between:

• valid optimal solutions
• non-convergence (cycling, degeneracy, unbounded problems)

Testing

• Existing doctests pass successfully
• Verified behavior on both converging and non-converging cases
• Confirmed ValueError is raised on iteration limit exceedance

[algorithms-keeper]

Closing this pull request as invalid

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