feat(local-inference): replace ollama with llama-swap + llama.cpp on zix790prors

- Add local-inference NixOS role using llama-swap (from nixpkgs-unstable)
  with llama.cpp (CUDA-enabled, from nixpkgs-unstable)
- Serves Qwen3.6-35B-A3B via HuggingFace auto-download with --cpu-moe
- Add nixosSpecialArgs for nixpkgs-unstable module access
- Configure opencode with llama-local provider pointing to zix790prors:8080
- Update gptel from Ollama backend to OpenAI-compatible llama-swap backend
- Remove ollama service from zix790prors

home/roles/emacs/doom/config.el

@@ -233,14 +233,15 @@ rbw is unavailable or the entry is not found."
          gptel-use-tools t
          gptel-confirm-tool-calls 'always
          gptel-include-reasoning 'ignore
-         gptel-model "qwen3:30b")
+         gptel-model "Qwen3.6-35B-A3B")
 
-  ;; Set default backend to be Ollama-Local
+  ;; Set default backend to llama-swap (OpenAI-compatible)
   (setq! gptel-backend
-         (gptel-make-ollama "Ollama-Local"
-           :host "localhost:11434"
+         (gptel-make-openai "llama-swap"
+           :host "localhost:8080"
+           :endpoint "/v1/chat/completions"
            :stream t
-           :models '(deepseek-r1 deepseek-r1-fullctx qwen3:30b qwen3:4b llama3.1 qwen2.5-coder mistral-nemo gpt-oss)))
+           :models '("Qwen3.6-35B-A3B")))
 
   ;; Define custom tools
   (gptel-make-tool