docs: Qwen3.8 spec-matrix benchmark page; add matrix tools; final env n_max=5

Recording the 54-config matrix, the realistic-prompt correction (n_max=5 not
10), the ubatch findings (256 is the safe/fast point), and the premature-stop
sampling-variance investigation.

docs/index.md

@@ -52,6 +52,7 @@ MTP-ONLY draft, port 7770]
 - [[Running Qwen3.6 35B A3B FP8 on Dankserver]] — MoE model (35B total, 3B active) on RTX 3090
 - [[Running Qwen3.6 27B FP8 on Dankclaw]] — Dense model (27B) on Strix Halo APU
 - [[frank-default-large-benchmark]] — backend/spec benchmark; chose MTP sidecar (2026-08-14) over DFlash (parallel premature-EOS bug)
+- [[qwen3.8-spec-matrix]] — Qwen3.8-27B UD-Q8_K_XL bundled-MTP spec matrix; winner draft-mtp n_max=5
 - [[frank-default-small-benchmark]] — ncmoe and batch/ubatch sweep that drove the Dankserver state
 - [[dankserver-vram-growth]] — VRAM/RAM growth investigation behind the recurring cuBLAS crash on frank-default-small
 - [[Dankclaw Improvements]] — researched enhancements: self-hosted agentic tools, runtime tuning, server/OS settings