feat(llm-inference): Day 1 playbook for RTX 3090 vLLM stack on astro-orbiter

- nvidia-driver-595-open (already installed 2026-08-03, idempotent)
- Python venv + vLLM 0.26.0 (already installed, idempotent)
- Gemma 2 27B model download via HuggingFace hub
- systemd vllm-serve.service on port 8000
- Hermes provider integration on carousel-of-progress
- vault_hf_token added to group_vars/all/vault
- ansible.cfg: vault_password_file set to absolute path
- inventory: astro_orbiter group added

Run with: env -u ANSIBLE_VAULT_PASSWORD_FILE ansible-playbook -i inventory.yml playbooks/day1_deploy_llm_inference.yml

ansible/roles/llm-inference/defaults/main.yml

@@ -0,0 +1,24 @@
+---
+# ------------------------------------------------------------------------------
+# FILE: roles/llm-inference/defaults/main.yml
+# DESCRIPTION: Overridable defaults for the llm-inference role.
+#              Deploy target: astro-orbiter (Dell OptiPlex 7050 SFF, RTX 3090
+#              via OCuLink, Ubuntu 24.04.4 LTS).
+# ------------------------------------------------------------------------------
+
+# NVIDIA driver
+llm_nvidia_driver_package: nvidia-driver-595-open
+
+# Python venv
+llm_venv_path: /home/jarvis/vllm-env
+llm_venv_owner: jarvis
+
+# HuggingFace
+llm_hf_cache_dir: /home/jarvis/.cache/huggingface
+llm_hf_model: google/gemma-2-27b-it
+
+# vLLM serve
+llm_serve_port: 8000
+llm_serve_host: "0.0.0.0"
+llm_gpu_memory_utilization: "0.90"
+llm_max_model_len: 8192