[Codex analysis][Acados v0.5.5][3/5] Solver modes and acceleration controls

[mickaelbegon]

Status: Codex analysis / WIP — no pull request will be opened for now.

This issue tracks the third Acados v0.5.5 analysis branch without adding a PR
to the maintainers' queue.

• WIP branch: mickaelbegon:codex/acados-v055-solver-modes
• Depends on: [Codex analysis][Acados v0.5.5][2/5] Safe code reuse and solver reset #1089 / codex/acados-v055-reuse-reset
• Codex implementation commit: 6720518a

Codex analysis

The comparison between Acados v0.5.1 and v0.5.5 identified two solver controls
that are both new in the upgrade range and directly useful to Bioptim:

• anderson_activation_threshold, paired with typed activation of depth-one
  Anderson acceleration for fixed-step SQP;
• byrd_omojokon_slack_relaxation_factor, used by
  SQP_WITH_FEASIBLE_QP to control slack relaxation.

The branch adds typed Bioptim options and setters for:

• with_anderson_acceleration;
• anderson_activation_threshold;
• byrd_omojokon_slack_relaxation_factor.

It also documents the Acados v0.5.5 QP solver list, including
PARTIAL_CONDENSING_CLARABEL. Clarabel is deliberately not enabled by default
in Bioptim's installer: the v0.5.5 build adds Rust/cbindgen requirements, and
its upstream macOS install target still assumes a Linux .so artifact.
Enabling it here would make the standard installation less reliable.

Validation performed by Codex

• Anderson acceleration with an explicit activation threshold converges on a
  Bioptim cube OCP;
• SQP_WITH_FEASIBLE_QP with an explicit Byrd–Omojokun factor converges on the
  same OCP;
• Acados interface suite: 33 passed;
• solver-options suite: 11 passed;
• origin/master remains at the stack baseline e8fbc729.

The existing defaults remain unchanged. This branch stays WIP until the
complete Acados analysis stack is ready for maintainer review.