more performance characterization work

docs/performance.md

@@ -7,6 +7,9 @@ Use `scripts/diff_performance_baseline.py` to compare a fresh run against that s
 
 The default baseline table below covers the standard example corpus only. The heavier `example_07_large_scale_routing_no_warm_start` canary remains performance-only and is tracked through targeted diffs plus the conflict/frontier trace artifacts.
 
+Use `scripts/characterize_pair_local_search.py` when you want a small parameter sweep over example_07-style no-warm runs instead of a single canary reading.
+The current tracked sweep output lives in `docs/pair_local_characterization.json` and `docs/pair_local_characterization.md`.
+
 | Scenario | Duration (s) | Total | Valid | Reached | Iter | Nets Routed | Nodes | Ray Casts | Moves Gen | Moves Added | Dyn Tree | Visibility Builds | Congestion Checks | Verify Calls |
 | :-- | --: | --: | --: | --: | --: | --: | --: | --: | --: | --: | --: | --: | --: | --: |
 | example_01_simple_route | 0.0040 | 1 | 1 | 1 | 1 | 1 | 2 | 10 | 11 | 7 | 0 | 0 | 0 | 4 |
@@ -31,6 +34,8 @@ For the current accepted branch, the most important performance-only canary is `
 - `pair_local_search_accepts`
 - `pair_local_search_nodes_expanded`
 
+The latest tracked characterization sweep confirms there is no smaller stable pair-local smoke case under the `<=1.0s` rule, so the 10-net no-warm-start canary remains the primary regression target for this behavior.
+
 Tracked metric keys:
 
 nodes_expanded, moves_generated, moves_added, pruned_closed_set, pruned_hard_collision, pruned_cost, route_iterations, nets_routed, nets_reached_target, warm_start_paths_built, warm_start_paths_used, refine_path_calls, timeout_events, iteration_reverify_calls, iteration_reverified_nets, iteration_conflicting_nets, iteration_conflict_edges, nets_carried_forward, score_component_calls, score_component_total_ns, path_cost_calls, danger_map_lookup_calls, danger_map_cache_hits, danger_map_cache_misses, danger_map_query_calls, danger_map_total_ns, move_cache_abs_hits, move_cache_abs_misses, move_cache_rel_hits, move_cache_rel_misses, guidance_match_moves, guidance_match_moves_straight, guidance_match_moves_bend90, guidance_match_moves_sbend, guidance_bonus_applied, guidance_bonus_applied_straight, guidance_bonus_applied_bend90, guidance_bonus_applied_sbend, static_safe_cache_hits, hard_collision_cache_hits, congestion_cache_hits, congestion_cache_misses, congestion_presence_cache_hits, congestion_presence_cache_misses, congestion_presence_skips, congestion_candidate_precheck_hits, congestion_candidate_precheck_misses, congestion_candidate_precheck_skips, congestion_grid_net_cache_hits, congestion_grid_net_cache_misses, congestion_grid_span_cache_hits, congestion_grid_span_cache_misses, congestion_candidate_nets, congestion_net_envelope_cache_hits, congestion_net_envelope_cache_misses, dynamic_path_objects_added, dynamic_path_objects_removed, dynamic_tree_rebuilds, dynamic_grid_rebuilds, static_tree_rebuilds, static_raw_tree_rebuilds, static_net_tree_rebuilds, visibility_corner_index_builds, visibility_builds, visibility_corner_pairs_checked, visibility_corner_queries_exact, visibility_corner_hits_exact, visibility_point_queries, visibility_point_cache_hits, visibility_point_cache_misses, visibility_tangent_candidate_scans, visibility_tangent_candidate_corner_checks, visibility_tangent_candidate_ray_tests, ray_cast_calls, ray_cast_calls_straight_static, ray_cast_calls_expand_snap, ray_cast_calls_expand_forward, ray_cast_calls_visibility_build, ray_cast_calls_visibility_query, ray_cast_calls_visibility_tangent, ray_cast_calls_other, ray_cast_candidate_bounds, ray_cast_exact_geometry_checks, congestion_check_calls, congestion_lazy_resolutions, congestion_lazy_requeues, congestion_candidate_ids, congestion_exact_pair_checks, verify_path_report_calls, verify_static_buffer_ops, verify_dynamic_candidate_nets, verify_dynamic_exact_pair_checks, refinement_windows_considered, refinement_static_bounds_checked, refinement_dynamic_bounds_checked, refinement_candidate_side_extents, refinement_candidates_built, refinement_candidates_verified, refinement_candidates_accepted, pair_local_search_pairs_considered, pair_local_search_attempts, pair_local_search_accepts, pair_local_search_nodes_expanded