feat(model-server): wizard V2 config modèles locaux — source, options structurées & preview

Refonte UX du wizard de configuration des modèles locaux du serveur
llama.cpp intégré, alignée sur la source Hugging Face et les options backend.

- choix de source sans jargon (chemin local .gguf vs dépôt Hugging Face) ;
- champs structurés -ngl (gpu_layers), -c (context_size), --jinja, --host ;
- zone d'arguments libres avec alerte sur les flags réservés ;
- preview de la commande via le backend (previewModelServerCommand, debounced) ;
- gateway/ports et mock adaptés au contrat V2.

QA : Vitest 22 verts, tsc/build OK.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/domain/index.ts

@@ -39,6 +39,17 @@ export type ModelServerStatus =
  */
 export type StopPolicy = "keepAlive" | "stopOnAppExit" | "stopWhenUnused";
 
+/**
+ * Where the served `.gguf` model comes from (F35 V2, mirror of the backend
+ * `ModelSourceDto`, camelCase wire, tagged on `type`):
+ * - `localPath`: an absolute `.gguf` path already present on disk (`--model`),
+ * - `huggingFace`: a `namespace/repo[:quant]` reference llama.cpp downloads and
+ *   caches automatically (`-hf`).
+ */
+export type ModelSource =
+  | { type: "localPath"; path: string }
+  | { type: "huggingFace"; repo: string };
+
 /**
  * A declared local model server (F35, mirror of the backend flat
  * `LocalModelServerConfigDto`, camelCase wire). Global to IdeA (not project
@@ -50,7 +61,8 @@ export type StopPolicy = "keepAlive" | "stopOnAppExit" | "stopWhenUnused";
  *   UUID; it does not generate the server id, only an internal model id it hides).
  * - `servedModelName` is what the user configures and what is sent to OpenCode as
  *   the `model` — the backend's internal `model.id`/`model.label` are not exposed.
- * - `modelPath` is required by the backend when `autoStart` is `true`.
+ * - `modelSource` (V2) replaces the former `modelPath`; it is required by the
+ *   backend when `autoStart` is `true`.
  */
 export interface LocalModelServerConfig {
   id: string;
@@ -60,17 +72,39 @@ export interface LocalModelServerConfig {
   /** OpenAI-compatible base URL served by `llama-server` (normalised to `/v1`). */
   baseURL: string;
   port: number;
-  /** Absolute `.gguf` path. Required when `autoStart` is `true`. */
-  modelPath?: string;
+  /** Explicit model source (`.gguf` path or Hugging Face ref). Required for auto-start. */
+  modelSource?: ModelSource;
   /** Model name exposed by the server and sent to OpenCode as `model`. */
   servedModelName: string;
   /** Explicit `llama-server` executable path/command (optional). */
   binaryPath?: string;
+  /** llama.cpp `--host` (default `127.0.0.1`). */
+  host: string;
+  /** llama.cpp `-ngl` GPU layers (optional; `0` = CPU only). */
+  gpuLayers?: number;
+  /** llama.cpp `-c` context size (optional). */
+  contextSize?: number;
+  /** Whether to pass `--jinja` (Jinja chat template). */
+  jinja: boolean;
   args: string[];
   autoStart: boolean;
   stopPolicy: StopPolicy;
 }
 
+/**
+ * A previewed `llama-server` command line (F35 V2, mirror of the backend
+ * `PreviewModelServerCommandDto`). Built by the backend from a draft config —
+ * never reconstructed client-side.
+ */
+export interface ModelServerCommandPreview {
+  /** Resolved executable (e.g. `llama-server` or an absolute path). */
+  command: string;
+  /** Argument vector, unescaped. */
+  args: string[];
+  /** Human-readable, shell-escaped command line. */
+  display: string;
+}
+
 /** A domain event relayed from the backend (tagged union on `type`). */
 export type DomainEvent =
   | { type: "projectCreated"; projectId: string }