feat(model-server): backend modèles locaux — serveur llama.cpp intégré (#35) et profils OpenCode locaux multiples (#36)

Sprint « Modeles locaux », couche backend (domain/application/infra/app-tauri).

#35 — Serveur de modèle local intégré (llama.cpp) :
- domain: model_server.rs (agrégat + statut), ports ModelServerProbe /
  ManagedProcess / ModelServerRuntime / ModelServerRegistry, événements
  model_server_status_changed et agent_launch_failed.
- application: use case EnsureLocalModelServer branché sur LaunchAgent.
- infrastructure: adapters HttpOpenAiCompatibleProbe, LlamaCppRuntime,
  LocalManagedProcess, FsModelServerRegistry.
- app-tauri: DTO plat LocalModelServerConfigDto, commandes
  list/save/delete_model_server avec garde model_server_in_use, wiring.

#36 — Profils OpenCode locaux multiples :
- domain: VO LocalModelServerId, OpenCodeConfig.local_model_server_id.
- application: use case CloneOpenCodeProfileFromSeed.
- app-tauri: commande clone_opencode_profile_from_seed, DTO/wiring.

Tests verts (exécution réelle) : domain+application OK, app-tauri
dto_model_servers 3/3 et dto_profiles 10/10, infra model_server 2/2,
application model_server+profile_usecases 19/19, cargo build workspace Finished.

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

crates/app-tauri/src/lib.rs

@@ -106,6 +106,8 @@ pub fn run() {
                             // If we killed first, the registry would be empty and every
                             // agent would be persisted as "closed".
                             let snapshot = std::sync::Arc::clone(&state.snapshot_running_agents);
+                            let model_servers =
+                                std::sync::Arc::clone(&state.ensure_local_model_server);
                             let open_projects = state.open_project_ids();
                             let handles = state.terminal_sessions.handles();
                             tauri::async_runtime::block_on(async move {
@@ -119,6 +121,7 @@ pub fn run() {
                                 for h in handles {
                                     let _ = pty.kill(&h).await;
                                 }
+                                let _ = model_servers.stop_on_app_exit().await;
                             });
                         }
                     }
@@ -156,8 +159,12 @@ pub fn run() {
             commands::detect_profiles,
             commands::list_profiles,
             commands::save_profile,
+            commands::clone_opencode_profile_from_seed,
             commands::delete_profile,
             commands::configure_profiles,
+            commands::list_model_servers,
+            commands::save_model_server,
+            commands::delete_model_server,
             commands::list_embedder_profiles,
             commands::save_embedder_profile,
             commands::delete_embedder_profile,