feat: overhaul upscale with bug fixes and advanced features

- Fix multi-image: process selected file, not always first
- Fix progress bar: asymptotic fill prevents visual stalling
- Fix slider: write results to captured index, not current selection
- Add model selection (Auto/AI/Fast), face enhancement, denoise
- Add output format (PNG/JPEG/WebP) with quality control
- Add Upscale All for sequential batch processing with queue
- More granular Python progress stages for smoother UX

apps/web/src/components/tools/upscale-settings.tsx

@@ -5,6 +5,12 @@ import { useToolProcessor } from "@/hooks/use-tool-processor";
 import { useFileStore } from "@/stores/file-store";
 
 const QUICK_SCALES = [2, 3, 4, 6, 8];
+const MODEL_OPTIONS = [
+  { value: "auto", label: "Auto" },
+  { value: "realesrgan", label: "AI" },
+  { value: "lanczos", label: "Fast" },
+] as const;
+const FORMAT_OPTIONS = ["png", "jpeg", "webp"] as const;
 
 export interface UpscaleControlsProps {
   onChange?: (settings: Record<string, unknown>) => void;
@@ -12,6 +18,11 @@ export interface UpscaleControlsProps {
 
 export function UpscaleControls({ onChange }: UpscaleControlsProps) {
   const [scale, setScale] = useState(2);
+  const [model, setModel] = useState<"auto" | "realesrgan" | "lanczos">("auto");
+  const [faceEnhance, setFaceEnhance] = useState(false);
+  const [denoise, setDenoise] = useState(0);
+  const [outputFormat, setOutputFormat] = useState<"png" | "jpeg" | "webp">("png");
+  const [quality, setQuality] = useState(95);
 
   const onChangeRef = useRef(onChange);
   useEffect(() => {
@@ -19,8 +30,15 @@ export function UpscaleControls({ onChange }: UpscaleControlsProps) {
   });
 
   useEffect(() => {
-    onChangeRef.current?.({ scale });
-  }, [scale]);
+    onChangeRef.current?.({
+      scale,
+      model,
+      faceEnhance,
+      denoise,
+      format: outputFormat,
+      quality,
+    });
+  }, [scale, model, faceEnhance, denoise, outputFormat, quality]);
 
   return (
     <div className="space-y-4">
@@ -56,21 +74,158 @@ export function UpscaleControls({ onChange }: UpscaleControlsProps) {
           className="w-full mt-2"
         />
       </div>
+
+      {/* Model */}
+      <div>
+        <p className="text-sm font-medium text-muted-foreground mb-1.5">Model</p>
+        <div className="flex gap-1">
+          {MODEL_OPTIONS.map(({ value, label }) => (
+            <button
+              key={value}
+              type="button"
+              onClick={() => setModel(value)}
+              className={`flex-1 text-xs py-1.5 rounded ${
+                model === value
+                  ? "bg-primary text-primary-foreground"
+                  : "bg-muted text-muted-foreground"
+              }`}
+            >
+              {label}
+            </button>
+          ))}
+        </div>
+        <p className="text-[11px] text-muted-foreground/70 mt-1">
+          {model === "auto" && "AI when available, falls back to fast resize"}
+          {model === "realesrgan" && "Real-ESRGAN neural network upscaling"}
+          {model === "lanczos" && "Fast Lanczos interpolation resize"}
+        </p>
+      </div>
+
+      {/* Face Enhancement */}
+      {model !== "lanczos" && (
+        <label className="flex items-center gap-2 cursor-pointer">
+          <input
+            type="checkbox"
+            checked={faceEnhance}
+            onChange={(e) => setFaceEnhance(e.target.checked)}
+            className="rounded border-border"
+          />
+          <span className="text-sm text-foreground">Enhance faces</span>
+        </label>
+      )}
+
+      {/* Denoise */}
+      <div>
+        <div className="flex justify-between items-center">
+          <p className="text-sm font-medium text-muted-foreground">Denoise</p>
+          <span className="text-sm font-mono font-medium">
+            {denoise === 0 ? "Off" : denoise.toFixed(1)}
+          </span>
+        </div>
+        <input
+          type="range"
+          min={0}
+          max={1}
+          step={0.1}
+          value={denoise}
+          onChange={(e) => setDenoise(Number(e.target.value))}
+          className="w-full mt-1"
+        />
+      </div>
+
+      {/* Output Format */}
+      <div>
+        <p className="text-sm font-medium text-muted-foreground mb-1.5">Output Format</p>
+        <div className="flex gap-1">
+          {FORMAT_OPTIONS.map((fmt) => (
+            <button
+              key={fmt}
+              type="button"
+              onClick={() => setOutputFormat(fmt)}
+              className={`flex-1 text-xs py-1.5 rounded uppercase ${
+                outputFormat === fmt
+                  ? "bg-primary text-primary-foreground"
+                  : "bg-muted text-muted-foreground"
+              }`}
+            >
+              {fmt}
+            </button>
+          ))}
+        </div>
+      </div>
+
+      {/* Quality (JPEG/WebP only) */}
+      {outputFormat !== "png" && (
+        <div>
+          <div className="flex justify-between items-center">
+            <p className="text-sm font-medium text-muted-foreground">Quality</p>
+            <span className="text-sm font-mono font-medium">{quality}</span>
+          </div>
+          <input
+            type="range"
+            min={1}
+            max={100}
+            step={1}
+            value={quality}
+            onChange={(e) => setQuality(Number(e.target.value))}
+            className="w-full mt-1"
+          />
+        </div>
+      )}
     </div>
   );
 }
 
 export function UpscaleSettings() {
-  const { files } = useFileStore();
+  const { files, entries } = useFileStore();
   const { processFiles, processing, error, downloadUrl, originalSize, processedSize, progress } =
     useToolProcessor("upscale");
   const [settings, setSettings] = useState<Record<string, unknown>>({});
 
+  // Queue mode for "Upscale All" - processes files sequentially
+  const queueRef = useRef(false);
+  const settingsRef = useRef(settings);
+  const prevProcessingRef = useRef(processing);
+
+  useEffect(() => {
+    settingsRef.current = settings;
+  });
+
+  // Auto-advance to next file when current one finishes
+  useEffect(() => {
+    if (prevProcessingRef.current && !processing && queueRef.current) {
+      const currentEntries = useFileStore.getState().entries;
+      const nextPending = currentEntries.findIndex((e) => e.status === "pending");
+      if (nextPending >= 0) {
+        useFileStore.getState().setSelectedIndex(nextPending);
+        setTimeout(() => processFiles(useFileStore.getState().files, settingsRef.current), 0);
+      } else {
+        queueRef.current = false;
+      }
+    }
+    prevProcessingRef.current = processing;
+  }, [processing, processFiles]);
+
   const handleProcess = () => {
     processFiles(files, settings);
   };
 
+  const handleProcessAll = () => {
+    queueRef.current = true;
+    const currentEntries = useFileStore.getState().entries;
+    const firstPending = currentEntries.findIndex((e) => e.status === "pending");
+    if (firstPending >= 0) {
+      useFileStore.getState().setSelectedIndex(firstPending);
+      setTimeout(() => processFiles(useFileStore.getState().files, settings), 0);
+    }
+  };
+
   const hasFile = files.length > 0;
+  const hasMultiple = files.length > 1;
+  const completedCount = entries.filter((e) => e.status === "completed").length;
+  const pendingCount = entries.filter((e) => e.status === "pending").length;
+  const allDone = entries.length > 0 && pendingCount === 0;
+  const isQueueActive = queueRef.current && processing;
 
   return (
     <div className="space-y-4">
@@ -79,6 +234,13 @@ export function UpscaleSettings() {
       {/* Error */}
       {error && <p className="text-xs text-red-500">{error}</p>}
 
+      {/* Multi-file progress summary */}
+      {hasMultiple && completedCount > 0 && (
+        <div className="text-xs text-muted-foreground bg-muted/50 rounded-lg px-3 py-2">
+          {completedCount} of {entries.length} images upscaled
+        </div>
+      )}
+
       {/* Size info */}
       {originalSize != null && processedSize != null && (
         <div className="text-xs text-muted-foreground space-y-0.5">
@@ -87,25 +249,41 @@ export function UpscaleSettings() {
         </div>
       )}
 
-      {/* Process button */}
+      {/* Process buttons / progress */}
       {processing ? (
         <ProgressCard
           active={processing}
           phase={progress.phase === "idle" ? "uploading" : progress.phase}
-          label="Upscaling image"
+          label={
+            isQueueActive
+              ? `Upscaling ${completedCount + 1} of ${entries.length}`
+              : "Upscaling image"
+          }
           percent={progress.percent}
           elapsed={progress.elapsed}
         />
       ) : (
-        <button
-          type="button"
-          data-testid="upscale-submit"
-          onClick={handleProcess}
-          disabled={!hasFile || processing}
-          className="w-full py-2.5 rounded-lg bg-primary text-primary-foreground font-medium disabled:opacity-50 disabled:cursor-not-allowed flex items-center justify-center gap-2"
-        >
-          {`Upscale ${(settings.scale as number) ?? 2}x`}
-        </button>
+        <div className="space-y-2">
+          <button
+            type="button"
+            data-testid="upscale-submit"
+            onClick={handleProcess}
+            disabled={!hasFile || processing}
+            className="w-full py-2.5 rounded-lg bg-primary text-primary-foreground font-medium disabled:opacity-50 disabled:cursor-not-allowed flex items-center justify-center gap-2"
+          >
+            {`Upscale ${(settings.scale as number) ?? 2}x`}
+          </button>
+          {hasMultiple && !allDone && (
+            <button
+              type="button"
+              onClick={handleProcessAll}
+              disabled={processing}
+              className="w-full py-2 rounded-lg border border-primary text-primary font-medium flex items-center justify-center gap-2 hover:bg-primary/5 disabled:opacity-50"
+            >
+              Upscale All ({pendingCount} remaining)
+            </button>
+          )}
+        </div>
       )}
 
       {/* Download */}