Audit rebase of PR 27 onto main

[mickaelbegon]

Audit rebase of #27 onto the current main base.

This branch keeps the original PR branch intact and publishes the rebased audit result for comparison.

What changed:

• Replayed the 16 commits from the original bioptim 3.4 migration branch onto pyomeca/cocofest:main.
• Resolved the environment.yml conflict by preserving the bioptim 3.4 solver pins and the dependency additions already present on the new base.
• Resolved the workflow rename/update conflict as run_tests.yml -> run_tests_win.yml.
• Resolved cycling example conflicts according to the PR-side migration, then let later commits remove or refine those files as in the original series.
• Added a small post-rebase fix so the bioptim 3.4 compatibility test imports pulse_width_optimization_mhe instead of the removed pulse_width_optimization_nmpc.

Validation:

• tests/shard1: 33 passed
• tests/shard2: 28 passed
• tests/shard1/test_bioptim_3_4_compat.py: 6 passed after the final post-rebase commit
• git diff --check: clean

Notes:

• Original PR branch remains untouched at 82cca095.
• Audit branch tip is 390c863.

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