dixie: unified KV per model; Qwen thinking sampling for the 9B

kv-unified lets one request use a model's whole 16k (split slots capped each at
8k and every Honcho dialectic prompt of 11-17k tokens failed). 9B gets temp 0.6 /
top-p 0.95 / top-k 20 / min-p 0: in a 20-batch replay of Honcho's deriver the
0.8 default dropped 7 batches (empty or wrong-shape output); with these, 3,
and 1 with a format instruction on rift. VRAM unchanged at 11.5 GB.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

hw/dixie/default.nix

@@ -31,6 +31,9 @@ let
     ; three resident models share 12 GB: keep contexts modest
     ctx-size = 16384
     parallel = 2
+    ; one KV pool per model shared by its slots, so a single long request can use all 16k
+    ; (split slots capped each at 8k: Honcho dialectic prompts of 11-17k all failed)
+    kv-unified = true
     cache-ram = 512
 
     ; Ornith 1.5 9B, refusal-ablated. Hermes auxiliary model (approval guardian, title,
@@ -40,6 +43,12 @@ let
     ; Runaway guard carried over from straylight: helper tasks need short answers.
     reasoning-budget = 2048
     n-predict = 4096
+    ; Qwen thinking-mode sampling (llama-server's 0.8 default made the Honcho deriver drop
+    ; ~1 in 3 batches, measured 2026-09-22). Clients that send their own temperature win.
+    temp = 0.6
+    top-p = 0.95
+    top-k = 20
+    min-p = 0
 
     ; Honcho dialectic: non-thinking instruct model so answers are short and fast.
     [honcho-dialectic]