transformers+vllm: 5-MOAD rescan; transformers-0004 CWE-407 all_special_ids per-loop rebuild in wav2vec2/esm

Rescan both targets against all 5 MOADs (2026-04-03).

New defect:
- transformers-0004: wav2vec2, wav2vec2_phoneme, esm tokenizers call
  self.all_special_ids/@property inside per-token decode loops, rebuilding
  list every iteration. O(T) -> O(1) fix: cache set before loop.
  wav2vec2_phoneme also has type mismatch (str vs list[int]), making
  the check always False, leaking special tokens.
  9/9 unit tests PASS.

Existing defects confirmed still present (not re-filed):
- transformers-0001/0002/0003: unchanged from 2026-03-31 scan.
- vllm-0001/0002: unchanged from 2026-03-31 scan.

MOAD-0002/0003/0004/0005: CLEAN on both targets (see SCAN-2026-04-03.md).

SCAN-TODO.md: marked transformers and vllm as complete with full summary.

Also includes UNDF stamps on jicofo-0001, jicofo-0002, langchain-0002 patches
from prior generate_undf.py run.

defects/langchain-0002/patch/langchain-0002-multi-query-unique-documents-quadratic.patch

@@ -1,3 +1,4 @@
+# UNDF: UNDF-2026-000001220
 --- a/libs/langchain/langchain_classic/retrievers/multi_query.py
 +++ b/libs/langchain/langchain_classic/retrievers/multi_query.py
 @@ -44,7 +44,22 @@ DEFAULT_QUERY_PROMPT = PromptTemplate(