[Codex analysis][Acados v0.5.5][1/5] Compatibility baseline

[mickaelbegon]

Status: Codex analysis / WIP — no pull request is currently open for this work.

This issue records a Codex analysis of the Acados v0.5.5 upgrade and points to
the corresponding implementation branch without adding another PR to the
maintainers' queue.

• WIP branch: mickaelbegon:codex/acados-v055-upgrade
• Former draft PR: [Acados v0.5.5][1/5] Upgrade compatibility baseline #1087 (closed to reduce the number of active PRs)
• Baseline: master at e8fbc729
• Acados update: v0.5.1 (48e223e) → v0.5.5 (59d93e17)

Codex analysis

Acados v0.5.5 changes its Python code-generation API and adds metadata
requirements for generated solvers. The branch currently:

• migrates Bioptim to AcadosOcp.code_gen_options;
• updates the bundled submodule to the official v0.5.5 tag;
• preserves the previous c_compile=False behavior as the compatibility baseline;
• updates Linux/macOS installation scripts and BLASFEO architecture defaults;
• installs the new link_libs.json and git_commit_hash metadata;
• updates macOS @rpath handling;
• adds a focused code-generation configuration test.

Validation performed by Codex

• native configure, build, and install on macOS arm64;
• generated libraries loaded without DYLD_LIBRARY_PATH;
• installer shell syntax validated;
• Acados interface suite: 29 tests passed.

Planned analysis branches

1. codex/acados-v055-upgrade — compatibility baseline (this issue)
2. codex/acados-v055-reuse-reset — safe generated-code reuse and solver reset
3. codex/acados-v055-solver-modes — relevant solver modes/options
4. codex/acados-v055-diagnostics — richer status and diagnostic reporting
5. codex/acados-v055-runtime-parameters — runtime parameter update paths

The branches remain WIP. A PR can be reopened or recreated later when
maintainers have capacity and the analysis scope has stabilized.