feat(model-server): source Hugging Face (-hf) + options structurées llama.cpp + migration store V2

Backend du support natif d'une source modèle Hugging Face en alternative au
chemin .gguf local pour le serveur llama.cpp intégré, et refonte des options.

- domaine : ModelSource {LocalPath|HuggingFace} + HfModelRef,
  LlamaCppOptions {host,gpu_layers,context_size,jinja}, invariant auto_start
  exigeant une source, validate_free_args (rejet des flags réservés).
- infra : build_argv partagé avec build_spawn_spec, émission -hf vs --model,
  ordre argv figé ; migration model-servers.json V1 -> V2.
- app-tauri : DTO V2 (modelSource, compat modelPath, conflit = INVALID),
  commande preview_model_server_command.

QA : cargo test ciblés verts (domain 7, application 8, infra model_server 4,
app-tauri dto 5). Échecs des suites complètes infra/app-tauri environnementaux
(sandbox bind/socket), hors périmètre.

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

crates/application/tests/model_server.rs

@@ -12,13 +12,13 @@ use application::{
 };
 use domain::events::DomainEvent;
 use domain::model_server::{
-    ExecutablePath, LocalModelRef, LocalModelServerConfig, LocalModelServerKind, ModelPath,
-    ModelServerEndpoint, ModelServerStatus, StopPolicy,
+    ExecutablePath, LlamaCppOptions, LocalModelRef, LocalModelServerConfig, LocalModelServerKind,
+    ModelPath, ModelServerEndpoint, ModelServerStatus, ModelSource, StopPolicy,
 };
 use domain::ports::{
     DirEntry, EventBus, EventStream, FileSystem, FsError, ManagedProcess, ManagedProcessHandle,
-    ModelServerError, ModelServerProbe, ModelServerRegistry, ModelServerRuntime, ProcessStatus,
-    ProfileStore, RemotePath, SpawnSpec, StoreError,
+    ModelServerArgv, ModelServerError, ModelServerProbe, ModelServerRegistry, ModelServerRuntime,
+    ProcessStatus, ProfileStore, RemotePath, SpawnSpec, StoreError,
 };
 use domain::profile::{AgentProfile, ContextInjection, OpenCodeConfig, StructuredAdapter};
 use domain::{LocalModelServerId, ProfileId, ProjectPath};
@@ -41,11 +41,14 @@ fn config(
         LocalModelRef::new(
             "qwen",
             "Qwen",
-            Some(ModelPath::new(path).unwrap()),
+            Some(ModelSource::LocalPath {
+                path: ModelPath::new(path).unwrap(),
+            }),
             "qwen3-coder-30b",
         )
         .unwrap(),
         Some(ExecutablePath::new("llama-server").unwrap()),
+        LlamaCppOptions::default(),
         Vec::new(),
         auto_start,
         StopPolicy::StopOnAppExit,
@@ -192,11 +195,16 @@ impl ManagedProcess for FakeProcess {
 struct FakeRuntime;
 
 impl ModelServerRuntime for FakeRuntime {
-    fn build_spawn_spec(
+    fn build_argv(
         &self,
         config: &LocalModelServerConfig,
-    ) -> Result<SpawnSpec, ModelServerError> {
-        Ok(SpawnSpec {
+    ) -> Result<ModelServerArgv, ModelServerError> {
+        let Some(ModelSource::LocalPath { path }) = config.model.source.as_ref() else {
+            return Err(ModelServerError::PathNotAccessible(
+                "model.source missing".to_owned(),
+            ));
+        };
+        Ok(ModelServerArgv {
             command: config
                 .binary
                 .as_ref()
@@ -204,10 +212,23 @@ impl ModelServerRuntime for FakeRuntime {
                 .unwrap_or_else(|| "llama-server".to_owned()),
             args: vec![
                 "--model".to_owned(),
-                config.model.path.as_ref().unwrap().as_str().to_owned(),
+                path.as_str().to_owned(),
                 "--port".to_owned(),
                 config.endpoint.port.to_string(),
+                "--host".to_owned(),
+                config.options.host.clone(),
             ],
+        })
+    }
+
+    fn build_spawn_spec(
+        &self,
+        config: &LocalModelServerConfig,
+    ) -> Result<SpawnSpec, ModelServerError> {
+        let argv = self.build_argv(config)?;
+        Ok(SpawnSpec {
+            command: argv.command,
+            args: argv.args,
             cwd: ProjectPath::new("/").unwrap(),
             env: Vec::new(),
             context_plan: None,
@@ -341,7 +362,14 @@ async fn absent_auto_start_spawns_and_waits_until_ready() {
     assert_eq!(spawns[0].command, "llama-server");
     assert_eq!(
         spawns[0].args,
-        vec!["--model", "/models/qwen.gguf", "--port", "8081"]
+        vec![
+            "--model",
+            "/models/qwen.gguf",
+            "--port",
+            "8081",
+            "--host",
+            "127.0.0.1"
+        ]
     );
 }