admin: surface CMF worker threads + GPU toggle in Settings

Expose the two speed knobs in the /admin Settings panel instead of TOML-only:
- [cmf].gpu (new) -> exports CMF_GPU=1 to the managed cortiq serve (Metal/wgpu).
  On Apple Silicon decode is memory-bandwidth bound so this is ~neutral for
  generation (helps prefill); off by default.
- [cmf].threads (added earlier) now has a UI number input.

- config.rs: CmfCfg.gpu bool (serde default false).
- cmf_runtime.rs: spawn_serve sets CMF_GPU=1 when gpu is on.
- admin/mod.rs: put_settings flags needs_restart on threads/gpu change (the
  server is spawned once at startup with those env vars).
- settings.js: threads input + gpu checkbox + save payload + speed hint.
- i18n en/ru: threads/gpu/speedNote keys (other locales fall back to en, as the
  whole cmf section already does there).

src/admin/mod.rs

@@ -655,9 +655,14 @@ async fn put_settings(State(state): State<SharedState>, Json(b): Json<SettingsBo
         cfg.cache = v;
     }
     if let Some(v) = b.cmf {
-        // manage_server / local_model changes apply on restart (the server is
-        // spawned at startup); local_only / router routing apply immediately.
-        if v.manage_server != cfg.cmf.manage_server || v.local_model != cfg.cmf.local_model {
+        // manage_server / local_model / threads / gpu apply on restart (the server
+        // is spawned once at startup with those env vars); local_only / router
+        // routing apply immediately.
+        if v.manage_server != cfg.cmf.manage_server
+            || v.local_model != cfg.cmf.local_model
+            || v.threads != cfg.cmf.threads
+            || v.gpu != cfg.cmf.gpu
+        {
             needs_restart = true;
         }
         cfg.cmf = v;

src/cmf_runtime.rs

@@ -167,6 +167,11 @@ fn spawn_serve(cfg: &CmfCfg) -> Result<Child, String> {
     if cfg.threads > 1 {
         cmd.env("CMF_THREADS", cfg.threads.to_string());
     }
+    // Offload large matvecs to the GPU (Metal on macOS). Memory-bandwidth-bound
+    // on unified memory, so mostly a prefill win; opt-in.
+    if cfg.gpu {
+        cmd.env("CMF_GPU", "1");
+    }
     cmd.stdout(Stdio::null())
         .stderr(Stdio::null())
         .kill_on_drop(true)

src/config.rs

@@ -116,6 +116,11 @@ pub struct CmfCfg {
     /// (measured ~2.8x faster than serial on a 15B model). Default 8.
     #[serde(default = "default_cmf_threads")]
     pub threads: usize,
+    /// Offload large matvecs to the GPU (exports CMF_GPU=1). On Apple Silicon the
+    /// decode loop is memory-bandwidth bound, so this is ~neutral for generation
+    /// (helps prefill of long prompts). Off by default.
+    #[serde(default)]
+    pub gpu: bool,
 }
 impl Default for CmfCfg {
     fn default() -> Self {
@@ -135,6 +140,7 @@ impl Default for CmfCfg {
             model_id: default_cmf_model_id(),
             local_only: false,
             threads: default_cmf_threads(),
+            gpu: false,
         }
     }
 }

web/js/i18n/en.js

@@ -239,6 +239,9 @@ export default {
   "settings.cmf.port": "Local server port",
   "settings.cmf.modelId": "Model id in the pool",
   "settings.cmf.note": "Serves a local .cmf via cortiq (github.com/infosave2007/cmf). Works even when the router is unavailable.",
+  "settings.cmf.threads": "Worker threads",
+  "settings.cmf.gpu": "Use GPU (Metal / wgpu)",
+  "settings.cmf.speedNote": "Threads parallelise the decode matvecs (~3x faster; 0 = runtime default). GPU offload mainly helps prefill of long prompts — decode is memory-bandwidth-bound, so on Apple Silicon it is roughly neutral.",
   "settings.router.taxonomy": "Taxonomy id",
   "settings.router.getKey": "Get or top up a router key at",
   "settings.router.secret": "Router key (value)",

web/js/i18n/ru.js

@@ -238,6 +238,9 @@ export default {
   "settings.cmf.port": "Порт локального сервера",
   "settings.cmf.modelId": "ID модели в пуле",
   "settings.cmf.note": "Обслуживает локальный .cmf через cortiq (github.com/infosave2007/cmf). Работает даже когда роутер недоступен.",
+  "settings.cmf.threads": "Рабочие потоки",
+  "settings.cmf.gpu": "Использовать GPU (Metal / wgpu)",
+  "settings.cmf.speedNote": "Потоки распараллеливают декод-матвеки (~×3; 0 = по умолчанию рантайма). GPU-оффлоад помогает в основном на prefill длинных промптов — декод упирается в пропускную способность памяти, поэтому на Apple Silicon почти нейтрален.",
   "settings.router.taxonomy": "ID таксономии",
   "settings.router.getKey": "Получить или пополнить ключ роутера:",
   "settings.router.secret": "Ключ роутера (значение)",

web/js/views/settings.js

@@ -193,6 +193,8 @@ export async function renderSettings() {
   const cmfModel = h("input", { value: s.cmf?.local_model || "", placeholder: "models/model.cmf" });
   const cmfPort = h("input", { type: "number", value: s.cmf?.local_port ?? 8081 });
   const cmfModelId = h("input", { value: s.cmf?.model_id || "cmf-local" });
+  const cmfThreads = h("input", { type: "number", min: 0, value: s.cmf?.threads ?? 8 });
+  const cmfGpu = check(t("settings.cmf.gpu"), s.cmf?.gpu);
 
   const saveBtn = h("button", { class: "btn primary" }, t("common.save"));
   saveBtn.addEventListener("click", async () => {
@@ -241,6 +243,8 @@ export async function renderSettings() {
         local_model: cmfModel.value.trim(),
         local_port: parseInt(cmfPort.value) || 8081,
         model_id: cmfModelId.value.trim() || "cmf-local",
+        threads: parseInt(cmfThreads.value) || 0,
+        gpu: cmfGpu.cb.checked,
       },
     };
     // serde: drop null optionals
@@ -373,7 +377,9 @@ export async function renderSettings() {
         h("div", { class: "row" }, cmfAutoInstall.node, cmfAutoUpdate.node),
         field(t("settings.cmf.model"), cmfModel),
         h("div", { class: "row" }, field(t("settings.cmf.port"), cmfPort), field(t("settings.cmf.modelId"), cmfModelId)),
-        h("div", { class: "hint" }, t("settings.cmf.note"))
+        h("div", { class: "row" }, field(t("settings.cmf.threads"), cmfThreads), cmfGpu.node),
+        h("div", { class: "hint" }, t("settings.cmf.note")),
+        h("div", { class: "hint" }, t("settings.cmf.speedNote"))
       )
     ),
     h(