feat(flight-ground): qualify physical transfer state

[d-sorgcodexagent]

Summary

• transfer solver-owned terminal flight state into the strict ground request without inventing contact state
• preserve terminal position, linear/angular velocity, ball/environment parameters, frames, provenance, and typed failure boundaries
• normally reconcile exact ground parent 6a2bc9d06f6f9a28a0d615b19d2ed4fc13871059 while preserving the declared PR base

Current evidence

• current head: 4972e55e0bb6e5b6bf7da0f899eed5d4f54e7d9d
• Python 3.11: 113 tests passed
• real Python 3.10.20: 113 tests passed
• Ruff/format, pinned mypy 1.13, structural budgets, campaign manifest/parity tests, docs governance, assertions, ancestry, and diff checks pass locally

Release boundary

This slice ends at flight-to-ground transfer. Impact impulse/repeated bounce (#4270), skid/roll (#4271), terrain/presets, total distance, UI/playback, Rust/WASM, and Upstream consumers remain open. Protected CI/review is required; merge this child into #4285 before collapsing the parent toward observer/wind.

Relates to #4269 and #4267.

[d-sorgcodexagent]

Exact-parent propagation update (2026-08-10):

• Published head: cdeb365f40d838dae40d1d13f23387dd87bf8eca
• Merge parents, in order: prior flight-transfer child 108a841b1378c992defd3c7b7ee263d41a6c8b24, quality-green strict-contract parent a93edb4bfd6a8dc9334122cd2ae660983d5bf424
• Branch/base preserved: feat/4269-flight-ground-transfer -> feat/4268-ground-contract
• Draft state preserved; no rebase, retarget, force-push, parent rewrite, or merge
• Conflict scope was limited to the four canonical handoff/spec files; no transfer production or test code conflicted
• Local evidence: 65 Python ground/transfer tests passed; documentation governance passed; changed-file size budget passed (0 violations); staged whitespace and conflict-marker checks passed
• Canonical handoffs and SPEC.md were updated in the same merge commit

Fresh exact-head protected CI and review remain required. Queued checks are not validation, and this partial transfer does not close the broader ground-model epic.

[d-sorgcodexagent]

Exact-head quality update: CI Standard quality-gate run 31435293793, job 93607957216, completed successfully for head cdeb365f40d838dae40d1d13f23387dd87bf8eca. The broader rollup remains pending on queued runner-backed checks and there is still no approval. This validates the current quality profile only; it is not a merge, release, or completion claim for the broader ground-model epic.

[dieterolson]

Consolidated into #4409. Closing to eliminate CI runner load.