## Summary
Implements the full revert-mode re-execution pipeline from the specification (§ Correction Flow, Revert Mode), enabling `agents plan correct --mode=revert` to truly re-execute from the targeted decision point rather than only logically marking decisions as superseded.
### Changes
- **Resource rollback**: `CorrectionService.execute_revert` now delegates to `CheckpointService.rollback_to_checkpoint` when a decision-aligned checkpoint exists, performing real `git reset --hard` in the sandbox. Gracefully degrades when checkpointing is unavailable.
- **Reasoning rollback**: Extracts `actor_state_ref` from the target decision's `ContextSnapshot` for downstream LangGraph actor restoration.
- **Guidance injection**: Generates a `user_intervention` decision ID for callers to record correction guidance in the decision tree.
- **Phase transition**: Signals that the plan should re-enter Strategize via `phase_transition_target="strategize"` on the result.
- **Model extension**: Added `checkpoint_restored`, `actor_state_ref`, `user_intervention_decision_id`, and `phase_transition_target` fields to `CorrectionResult` with backward-compatible defaults.
- **Dispatch update**: `execute_correction` now accepts and forwards a `decisions` parameter.
### Design Approach
Uses a signal-based architecture: rather than having `CorrectionService` directly manipulate plan state or LangGraph actors, the enhanced `execute_revert` returns signal fields on `CorrectionResult` that downstream consumers use for the full pipeline. This preserves separation of concerns.
### Tests
- **Behave**: 16 new BDD scenarios in `features/revert_re_execution.feature`
- **Robot**: 7 integration tests in `robot/revert_re_execution.robot`
- **Coverage**: 98% (above 97% threshold)
### Quality Gates
| Gate | Status |
|------|--------|
| `nox -s lint` | Pass |
| `nox -s typecheck` | Pass (0 errors) |
| `nox -s unit_tests` | Pass (12376 scenarios, 0 failed) |
| `nox -s integration_tests` | Pass (1631 passed, 3 pre-existing failures #647) |
| `nox -s e2e_tests` | Pass (37 passed) |
| `nox -s coverage_report` | Pass (98%) |
Closes#844
Reviewed-on: #1153
Co-authored-by: Brent E. Edwards <brent.edwards@cleverthis.com>
Co-committed-by: Brent E. Edwards <brent.edwards@cleverthis.com>
