Stop Firefox from squashing upload tiles and show IQDB queue progress

The upload grid was its own scroll container (max-height + overflow on the
same element). Firefox sizes auto grid rows to min-content in that setup,
so every tile collapsed to its footer height and the image was clipped to a
wide strip; Chromium sizes them to max-content, which is why this only
showed up in the user's browser. auto-rows-max pins rows to max-content in
both; verified with headless Firefox screenshots and Chromium measurements
(60 tiles render 152x194 each, 1845px of content in a 639px scroller).
The box is now 70vh so it behaves as a proper fixed gallery area with its
own scrollbar instead of shrinking with the item count.

IQDB progress: the page header now shows a live 'Checking IQDB — x/y'
counter with a bar while background checks run, so the queue is visible
without opening the per-file modal (which keeps its spinner, candidates
and per-file errors).

frontend/src/features/upload/UploadPage.tsx

@@ -679,6 +679,10 @@ export default function UploadPage() {
   const [processing, setProcessing] = useState(false);
   const [checkingIds, setCheckingIds] = useState<string[]>([]);
   const [checkErrors, setCheckErrors] = useState<Record<string, string>>({});
+  const [iqdbProgress, setIqdbProgress] = useState<{
+    done: number;
+    total: number;
+  } | null>(null);
   const [modalId, setModalId] = useState<string | null>(null);
   const [bulkOpen, setBulkOpen] = useState(false);
 
@@ -796,6 +800,10 @@ export default function UploadPage() {
       for (const temp of targets) {
         if (!temp.file_url) continue;
         if (/\.(mp4|webm)$/i.test(temp.original_filename)) continue;
+        setIqdbProgress((current) => ({
+          done: current?.done ?? 0,
+          total: (current?.total ?? 0) + 1,
+        }));
         try {
           const blob = await fetchTempBlob(temp.file_url);
           const results = await iqdbSearch(
@@ -822,6 +830,9 @@ export default function UploadPage() {
             [temp.temp_id]: describeError(error),
           }));
         } finally {
+          setIqdbProgress((current) =>
+            current ? { ...current, done: current.done + 1 } : current,
+          );
           setCheckingIds((current) =>
             current.filter((value) => value !== temp.temp_id),
           );
@@ -830,6 +841,9 @@ export default function UploadPage() {
     } finally {
       setProcessing(false);
       setCheckingIds([]);
+      setIqdbProgress((current) =>
+        current === null || current.done >= current.total ? null : current,
+      );
       invalidateUploads();
     }
   }
@@ -1010,14 +1024,30 @@ export default function UploadPage() {
           </p>
         </div>
         {busy || processing ? (
+          <div className="flex w-56 flex-col gap-1.5">
             <p className="flex items-center gap-2 text-xs text-ctp-overlay0">
-            <Spinner className="h-3.5 w-3.5" />
+              <Spinner className="h-3.5 w-3.5 shrink-0" />
+              <span className="truncate">
                 {busy
                   ? `Uploading ${Math.min(uploadedCount + 1, entries.length)}/${entries.length}…`
-              : checkingIds.length > 0
+                  : iqdbProgress
-                ? `Checking ${checkingIds.length} file(s) against IQDB…`
+                    ? `Checking IQDB — ${iqdbProgress.done}/${iqdbProgress.total}`
                     : "Processing uploads…"}
+              </span>
             </p>
+            {!busy && iqdbProgress ? (
+              <div className="h-1 overflow-hidden rounded-full bg-ctp-surface0">
+                <div
+                  className="h-full bg-ctp-teal transition-[width]"
+                  style={{
+                    width: `${Math.round(
+                      (iqdbProgress.done / iqdbProgress.total) * 100,
+                    )}%`,
+                  }}
+                />
+              </div>
+            ) : null}
+          </div>
         ) : null}
       </header>
 
@@ -1120,7 +1150,10 @@ export default function UploadPage() {
               ))}
             </div>
           ) : null}
-          <div className="grid max-h-[60vh] grid-cols-[repeat(auto-fill,minmax(150px,1fr))] content-start gap-3 overflow-y-auto overscroll-contain pr-1">
+          {/* auto-rows-max: when the grid is its own scroll container Firefox
+              sizes auto rows to min-content and squashes the tiles; max-content
+              keeps every tile at its aspect-ratio size and scrolls instead. */}
+          <div className="grid max-h-[70vh] auto-rows-max grid-cols-[repeat(auto-fill,minmax(150px,1fr))] content-start gap-3 overflow-y-auto overscroll-contain pr-1">
             {entries.map((entry) => (
               <div
                 key={entry.id}