frank-primary: roll back to qwen FP8 + MTP4 (2339fae trio)

DFlash2 experiment declared failed 2026-10-01: the drafter serves and
drafts (12.8 tok/s proposed) but acceptance is pinned at 1.0-1.38 on ALL
text classes including verbatim repetition — the aux-hidden-state capture
semantics are wrong (single-stream entering-state vs post-layer/comb is
the untested alternative). At ~1.2 acceptance the 8-token verify tax makes
decode 5x SLOWER than the 9.9-10.0 baseline (1.6-1.8 tok/s measured).

Restores the verified 37-40 tok/s shape: qwen3.8-flash-next FP8, MTP4,
prefetch off, 200k x 3 seqs, fp8 KV.

scripts/patches/glm53-dflash-03-kv-unify-tailpin.patch

@@ -1,37 +0,0 @@
---- a/vllm/v1/core/kv_cache_utils.py
-+++ b/vllm/v1/core/kv_cache_utils.py
-@@ -1395,10 +1395,34 @@
-         return kv_cache_spec
- 
-     max_page_size = max(page_sizes)
-+    # GLM-5.3-Flash + a draft model: the sparse indexer k_cache page is
-+    # tokens_per_state x the MLA page (same per-token bytes), and MLA layers
-+    # cannot be PADDED to an arbitrary page size (sparse MLA indexes the cache
-+    # in whole token rows) -- but they CAN grow their block size when the max
-+    # page is an exact multiple of the MLA page. Bump the max page to a
-+    # multiple of every MLA-family page so all of them take the divisible
-+    # block-growth branch below instead of the padding refusal, while the
-+    # draft and mamba layers simply pad to the (slightly larger) page.
-+    mla_pages = {
-+        spec.page_size_bytes
-+        for spec in kv_cache_spec.values()
-+        if isinstance(spec, MLAAttentionSpec)
-+    }
-+    if mla_pages:
-+        mla_common = math.lcm(*mla_pages)
-+        max_page_size = -(-max_page_size // mla_common) * mla_common
-     new_kv_cache_spec = {}
-     for layer_name, layer_spec in kv_cache_spec.items():
-         if layer_spec.page_size_bytes == max_page_size:
-             new_kv_cache_spec[layer_name] = layer_spec
-+        elif isinstance(layer_spec, KpoolTailSpec):
-+            # The kpool tail kernel pins the tail block to the kpool size
-+            # (tail_kv_cache.view(...) must be [blocks, 2, index_kpool,
-+            # head_dim]); growing block_size breaks that contract. Pad the
-+            # physical page instead -- the tail is its own group and the pad
-+            # wastes bytes only.
-+            new_spec = replace(layer_spec, page_size_padded=max_page_size)
-+            new_kv_cache_spec[layer_name] = new_spec
-         elif isinstance(layer_spec, MambaSpec):
-             # MambaSpec's page size is determined by its state shapes and does
-             # not scale with block_size, so pad the page instead. This is the