game-engines: allegro5/bullet3/box2d/dry CWE-407 scan

bullet3-0001: btGhostObject::addOverlappingObjectInternal O(N²) linear dedup
  per broadphase step — even carries "too slow" self-admission comment (HIGH)
bullet3-0002: btSoftRigidCollisionAlgorithm::processCollision O(C×D) per
  frame on m_collisionDisabledObjects plain array (MEDIUM)
allegro5: CLEAN (vector_contains only on non-hot setup paths)
box2d: CLEAN (v3 rewrite uses b2HashSet throughout)
dry: CLEAN (HashSet/HashMap on all hot dedup paths)

defects/dask/patch/CLEAN.md

@@ -0,0 +1,18 @@
+# dask — CWE-407 Scan: CLEAN
+
+Scanned: 2026-03-29
+
+## Scope
+
+- `dask/optimization.py` — fuse_linear, fuse: `seen = set()`
+- `dask/_task_spec.py` — graph traversal: `seen = set()`
+- `dask/highlevelgraph.py` — dependency walk: `seen = set()`
+- `dask/dot.py` — DAG visualization: `seen = set()`
+- `dask/order.py` — transitive_deps dedup: `transitive_deps_ids = set()` (list used only for ordered iteration, dedup via set)
+- `dask/dataframe/dask_expr/_expr.py` — `ancestors = []` is a pure accumulator list (not used for membership checks; dedup done via `seen = set()` at line 3192)
+
+## Verdict
+
+No CWE-407 (algorithmic complexity / quadratic membership check) defects found.
+All visited/seen deduplication uses `set` or `dict` throughout the task graph
+traversal and optimization paths.