llm-router: CPU-offload Coder-14B + Llama-3.1-8B (t_72646029)

- Remove global --n-gpu-layers from router unit ExecStart in preset mode
  (llama.cpp CLI arg outranked per-model INI n-gpu-layers=0; root cause from
  War Machine's run 1). Flag now emitted only in --models-dir mode.
- All 5 preset INI sections carry explicit n-gpu-layers:
  Qwen3.8=99, Phi=99, nomic=99, Coder=0, Llama=0.
- host_vars/astro-orbiter: llm_router_models_max 2 -> 4 so CPU-offloaded
  models count as loaded without LRU-evicting Qwen3.8.
- defaults: llm_router_coder_gpu_layers / llm_router_llama_gpu_layers = 0.
- verify.yml: fix pre-existing .meta attribute crash in router mode.
- New playbook day2_cpu_offload_aux_models.yml.

Deployed + verified on astro-orbiter (gates A-E PASS): concurrent residency
achieved, Qwen3.8 stays GPU-resident. Measured CPU throughput Llama 9.0 /
Coder 4.7 tok/s. VRAM note: llama.cpp 6ea215d allocates ~1.4-1.7GB CUDA-context
per CPU model even at n-gpu-layers=0 -> ~24,004 MiB steady-state, below the
24,576 MiB physical limit. Comments corrected to match the measurement.
Report: friday/inbox/ryan/2026-08-17-llm-cpu-offload-coder-llama-deployed.md

ansible/host_vars/astro-orbiter/vars.yml

@@ -65,10 +65,16 @@ common_root_lv: ubuntu-lv
 # auxiliary models evict it on demand, and vice versa).
 # NOTE: Qwen3.8 does NOT have load-on-startup — it loads on first request.
 # This avoids an LRU eviction race with nomic-embed at startup.
-# UPDATED (t_441470b9, 2026-08-16): ctx bumped to 131072 (128K). Measured
-# VRAM: 20,282 MiB at 131072 ctx. nomic-embed 558 MiB always resident ->
-# ~20.8GB total, ~3.2GB headroom. models-max=2 unchanged (same constraint).
-llm_router_models_max: 2
+# UPDATED (t_72646029, 2026-08-17): CPU offload for Coder + Llama changes the
+# constraint. Coder and Llama now use CPU inference (n-gpu-layers=0). GPU-resident
+# VRAM: Qwen3.8 (~20,302 MiB at 128K ctx) + nomic-embed (558 MiB, pinned) plus the
+# CUDA-context buffers llama.cpp 6ea215d allocates for the CPU models (~1.4-1.7GB
+# each) = ~24,004 MiB steady-state, below the 24,576 MiB physical limit.
+# models-max raised to 4: nomic (slot 1, pinned) + Qwen3.8 (slot 2, GPU) +
+# Llama (slot 3, CPU) + Coder (slot 4, CPU). Phi (GPU, ~8.3GB) can still be
+# requested but evicts Qwen3.8 due to VRAM constraint. models-max=4
+# is required so CPU-offloaded models count as loaded without evicting Qwen3.8.
+llm_router_models_max: 4
 
 llm_staged_models:
   - filename: "Phi-3.5-mini-instruct-Q8_0.gguf"