llm-inference-multimodel: add Qwen2.5-14B shadow instance (port 8002, gated off — VRAM co-residency not yet confirmed)

- New llama-server-qwen systemd unit template, gated by llm_qwen_service_enabled (default false)
- Idempotent GGUF download task (bartowski Qwen2.5-14B-Instruct-Q5_K_M, stat-guarded)
- Launch flags per local-llm-64k-context-recommendation.md: ctx-size 65536, flash-attn, q8_0 KV cache, batch 2048/ubatch 512, jinja, parallel 1
- verify.yml only starts/verifies the qwen unit when llm_qwen_service_enabled=true
- README: documents live VRAM gate finding (nvidia-smi 2026-08-06: Phi-4+Mistral already ~16.6/24GB, ~7.5GB free -- insufficient for Qwen weights concurrently) and options
- Does NOT touch llama-server-aux (8000) or llama-server-toolcall (8001) service state

ansible/roles/llm-inference-multimodel/tasks/models.yml

@@ -97,3 +97,28 @@
     group: "{{ llm_service_user }}"
     mode: "0644"
   become: true
+
+# --- Shadow model (Qwen2.5-14B-Instruct Q5_K_M, port 8002) --------------------
+# Downloaded unconditionally (so the ~10.5GB file is staged ahead of any VRAM
+# decision) — only the *service start* is gated by llm_qwen_service_enabled
+# (see verify.yml / VRAM gate note in defaults/main.yml).
+
+- name: Check if Qwen shadow model GGUF already exists
+  ansible.builtin.stat:
+    path: "{{ llm_qwen_model_path }}"
+  register: llm_qwen_model_stat
+
+- name: Download Qwen2.5-14B-Instruct-Q5_K_M GGUF (bartowski quant)
+  ansible.builtin.get_url:
+    url: "{{ llm_qwen_model_url }}"
+    dest: "{{ llm_qwen_model_path }}"
+    headers:
+      Authorization: "Bearer {{ llm_hf_token }}"
+    owner: "{{ llm_service_user }}"
+    group: "{{ llm_service_user }}"
+    mode: "0644"
+    timeout: 7200
+    force: false
+  become: true
+  no_log: true
+  when: not llm_qwen_model_stat.stat.exists or (llm_qwen_model_stat.stat.size | int) < (llm_qwen_model_min_bytes | int)