[Wave RHO][3/4] Preserve receding-horizon outcomes and expose Acados diagnostics

[mickaelbegon]

Note

Wave RHO 3/4 — Draft/WIP. Tracking issue: #1086.

This wave and its decomposition come from an analysis performed by OpenAI Codex. Maintainer review is required before these proposals are considered ready.

Wave RHO context

The overall goal is to upstream generic, application-independent foundations for reliable receding-horizon workflows with IPOPT and Acados: solver-input correctness, supported warm-start grid transfer, explicit window outcomes/diagnostics/hooks, and finally supported solver tuning.

Proposed review/merge order:

1. [Wave RHO][1/4] Fix Acados control-bound scaling and ordering #1075 — Acados control-bound correctness
2. [Wave RHO][2/4] Adapt solutions to new initial-guess grids #1073 — solution-to-initial-guess grid adaptation
3. [Wave RHO][3/4] Preserve receding-horizon outcomes and expose Acados diagnostics #1072 — RHO outcomes, hooks, cyclic shifts, diagnostics, and iterate access
4. [Wave RHO][4/4] Expose supported advanced Acados options #1074 — advanced Acados options

Role of this PR: core RHO orchestration and observability layer.

Interaction: Reviewed after #1075 and #1073 because correct Acados inputs and supported warm-start transfer frame how these outcomes, hooks, shifts, and iterates are consumed.

All four PRs target master independently; this is an interaction/review order, not a stacked Git dependency.

What changed

• preserve each receding-horizon window's actual solver status and export decision
• distinguish numerical success, trajectory availability and explicit physical acceptance
• add stop/diagnostic continuation policies and before/after window hooks
• expose Acados diagnostics and stable primal/dual iterate access
• add configurable cyclic state shifts without assuming a variable index or 2*pi period
• make Acados multiplier warm starts explicit and compatibility-checked

Why

Failed Acados windows could previously be exported and counted implicitly while the aggregate solution lost their status. Downstream applications also had to access private Acados objects for diagnostics and iterates.

Validation

• pytest -q tests/shard2/test_receding_horizon_status.py tests/shard2/test_receding_horizon_hooks_and_shifts.py
• 3 passed, 2 skipped when acados_template is unavailable

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