Extended _compute_affected_subtree() to BFS over both the structural tree
(parent-child plan relationships) and decision_dependencies edges (influence
DAG). The algorithm performs a single O(V+E) BFS pass that unions neighbors
from both edge sources, using a visited set for cycle detection to guard
against data corruption.
Decision creation now supports dependency_decision_ids parameter in
record_decision() which populates the in-memory influence DAG store.
get_influence_edges() returns the adjacency list format consumed by
CorrectionService.
All public CorrectionService methods (analyze_impact, execute_revert,
execute_correction, generate_dry_run_report) accept an optional
influence_edges parameter while remaining backward-compatible (defaults
to None, preserving structural-only traversal when not provided).
Key design decisions:
- Single BFS pass over union of structural + influence edges rather than
separate traversals, ensuring O(V+E) complexity and consistent visit order
- Cycle detection via visited set with warning log (not an error) since
cycles indicate data corruption, not a programming error
- Influence edge logging: traversal emits count of influence edges processed
for observability
- Backward-compatible API: existing callers that only pass decision_tree
continue to work identically
ISSUES CLOSED: #542
