straylight: llama presets for the Primer's chapter 50 student models

straylight-student serves Qwen3-4B at Q8_0; straylight-student-tuned serves
the same base with the LoRA adapter trained on dixie on 2026-10-26. Both
read from /var/lib/llama-server/models/aec-ch50 with one 16k slot.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

hw/straylight/default.nix

@@ -166,6 +166,21 @@ let
     parallel = 1
     ctx-size = 32768
     dedup-cache-models = true
+
+    ; The Primer, chapter 50: Qwen3-4B at Q8_0 (converted from the HF checkpoint
+    ; at 1cfa9a72) as the student, and the same base with the LoRA adapter trained
+    ; on dixie (2026-10-26) from the 35B's tool-use traces. The before/after eval
+    ; compares the two. One 16k slot each: the suite's turns are short.
+    [straylight-student]
+    model = ${llamaModelsDir}/aec-ch50/qwen3-4b-Q8_0.gguf
+    parallel = 1
+    ctx-size = 16384
+
+    [straylight-student-tuned]
+    model = ${llamaModelsDir}/aec-ch50/qwen3-4b-Q8_0.gguf
+    lora = ${llamaModelsDir}/aec-ch50/adapter.gguf
+    parallel = 1
+    ctx-size = 16384
   '';
   # `llama-models` shows what the router has resident; `llama-unload` frees every loaded
   # model (e.g. before a gaming session), or just the ones named on the command line.