fix(studio): a repair lands under the brush with no pill over it, and a browser with no device is not asked for one

docker/frontend/src/App.tsx

@@ -1050,7 +1050,12 @@ export function Workspace() {
     if (!engine || !previewBytes || shooting) return;
     const token = ++renderToken.current;
     const timer = setTimeout(async () => {
-      setBusy(t('act.rendering'));
+      // No spinner for this one, deliberately. The render is the page keeping up
+      // with the reader — the brush's own spots are already drawn on the layer
+      // above the photo, so the repair arriving under them a moment later is the
+      // photo catching up and not a thing being waited for. A pill saying so was
+      // read as the studio doing something to the frame (an export, a second
+      // copy), and it stayed up through a HEAL long enough to be noticed.
       try {
         // The geometry is the frame's own; only the recipe differs between the
         // render and the compare copy, so the two can never drift apart.

docker/frontend/src/engine/inpaint.ts

@@ -71,16 +71,32 @@ async function warmsUp(ort: typeof Ort, session: Ort.InferenceSession): Promise<
   }
 }
 
+// Whether the browser has a device at all. `requestAdapter` answers for the
+// browser and not for this graph — an adapter is no promise the model runs on
+// it, the trial below is what settles that — but a *null* answer is a promise
+// it does not, and the attempt it saves is not nothing: a `create` that cannot
+// have a device still opens a session and tears it down (measured: 0.4s off the
+// first repair, and one backend fewer built on the way to the one that lasts).
+async function hasDevice(): Promise<boolean> {
+  try {
+    return Boolean(await navigator.gpu?.requestAdapter());
+  } catch {
+    return false;
+  }
+}
+
 // WebGPU first, the processor as the answer to every way that can fail: no
 // adapter, no `shader-f16` needed here but an op the provider never
 // implemented, a driver that opens a session and dies on the first dispatch.
 async function openSession(ort: typeof Ort): Promise<Ort.InferenceSession> {
-  try {
-    const gpu = await ort.InferenceSession.create(MODEL_URL, { executionProviders: ['webgpu'] });
-    if (await warmsUp(ort, gpu)) return gpu;
-    await gpu.release();
-  } catch {
-    // Whatever went wrong, the wasm provider is the fallback and not a failure.
+  if (await hasDevice()) {
+    try {
+      const gpu = await ort.InferenceSession.create(MODEL_URL, { executionProviders: ['webgpu'] });
+      if (await warmsUp(ort, gpu)) return gpu;
+      await gpu.release();
+    } catch {
+      // Whatever went wrong, the wasm provider is the fallback and not a failure.
+    }
   }
   return ort.InferenceSession.create(MODEL_URL, { executionProviders: ['wasm'] });
 }

docker/frontend/src/i18n/en.ts

@@ -28,9 +28,6 @@ export const en: Dict = {
   'act.reset': 'RESET',
   'act.export': 'EXPORT',
   'act.exporting': 'Exporting…',
-  // The stage's own re-render behind a brush stroke or a knob: no file is being
-  // written anywhere, and "Exporting…" over a HEAL was read as exactly that.
-  'act.rendering': 'Rendering…',
   'act.upscaling': 'Upscaling the photo {done}/{total}…',
   'act.cancel': 'Cancel',
 

docker/frontend/src/i18n/vi.ts

@@ -39,7 +39,6 @@ export const vi = {
   'act.reset': 'ĐẶT LẠI',
   'act.export': 'XUẤT ẢNH',
   'act.exporting': 'Đang xuất…',
-  'act.rendering': 'Đang dựng ảnh…',
   'act.upscaling': 'Đang phóng to ảnh {done}/{total}…',
   'act.cancel': 'Huỷ',