feat(ground): bind regional plan execution and evidence

[d-sorgcodexagent]

Summary

• bind regional ground execution to the exact embedded material plan and canonical ground-request identity
• add a strict Python/TypeScript ground-regional-execution-result/v1 evidence envelope without claiming TypeScript physics
• validate every transition ledger row against a real plan boundary and the corresponding frozen ground-result event
• represent cancellation and execution failures truthfully as typed null-result outcomes

Verification

• 143 focused Python ground tests and 24 focused React contract/editor tests
• independent rerun: 59 Python and 10 React tests
• Ruff, format, Bandit, strict/coherent MyPy, TypeScript, ESLint, production build, docs, manifest, size, structure, ancestry, and diff gates

Remaining boundaries

This is a UI-neutral execution/contract slice. Regional playback controls, measured calibration, changing geometry, compiled/TypeScript regional physics, downstream consumer parity, and protected release evidence remain open under #4267 and #4271.

Addresses #4271
Part of #4267

[dieterolson]

Consolidated into #4409. Closing to reduce CI/CD runner load.