fix: add failed tag locate and filter controls

Add a failed-tag discovery flow for background worker failures.

Changes:
- Add a Failed Tags toolbar filter that appears when tag failures exist.
- Add Locate buttons for failed tag tasks in the background worker prompt.
- Route Locate to the affected folder and filter the gallery to images with tagger errors.
- Fetch and display failed tag filenames/errors in the expanded worker details.
- Add a backend query and gallery filter flag for images with failed AI tagging.
- Improve subtle-light contrast for failed worker chips, filenames, and Locate/Retry buttons.
- Also slightly increases the title bar update indicator pulse size for better visibility.

src/components/Toolbar.tsx

@@ -158,6 +158,8 @@ export function Toolbar() {
   const setMinimumRating = useGalleryStore((state) => state.setMinimumRating);
   const failedEmbeddingsOnly = useGalleryStore((state) => state.failedEmbeddingsOnly);
   const setFailedEmbeddingsOnly = useGalleryStore((state) => state.setFailedEmbeddingsOnly);
+  const failedTaggingOnly = useGalleryStore((state) => state.failedTaggingOnly);
+  const setFailedTaggingOnly = useGalleryStore((state) => state.setFailedTaggingOnly);
   const similarScope = useGalleryStore((state) => state.similarScope);
   const setSimilarScope = useGalleryStore((state) => state.setSimilarScope);
   const mediaJobProgress = useGalleryStore((state) => state.mediaJobProgress);
@@ -166,6 +168,7 @@ export function Toolbar() {
   const activeView = useGalleryStore((state) => state.activeView);
 
   const hasAnyFailedEmbeddings = Object.values(mediaJobProgress).some((p) => p.embedding_failed > 0);
+  const hasAnyFailedTagging = Object.values(mediaJobProgress).some((p) => p.tagging_failed > 0);
 
   const [searchCommand, setSearchCommand] = useState<SearchCommand | null>(null);
   const [searchQuery, setSearchQuery] = useState(search);
@@ -441,12 +444,12 @@ export function Toolbar() {
 
       {/* Filter row */}
       <div className="flex items-center gap-1 px-4 pb-1.5">
-        <FilterPill label="All" active={mediaFilter === "all" && !favoritesOnly && !failedEmbeddingsOnly && minimumRating === 0} onClick={() => { setMediaFilter("all"); setFavoritesOnly(false); setMinimumRating(0); setFailedEmbeddingsOnly(false); }} />
-        <FilterPill label="Images" active={mediaFilter === "image" && !favoritesOnly && !failedEmbeddingsOnly} onClick={() => { setMediaFilter("image"); setFavoritesOnly(false); setFailedEmbeddingsOnly(false); }} />
-        <FilterPill label="Videos" active={mediaFilter === "video" && !favoritesOnly && !failedEmbeddingsOnly} onClick={() => { setMediaFilter("video"); setFavoritesOnly(false); setFailedEmbeddingsOnly(false); }} />
-        <FilterPill label="Favorites" active={favoritesOnly} onClick={() => { setFavoritesOnly(!favoritesOnly); setFailedEmbeddingsOnly(false); }} />
-        <FilterPill label="Rated" active={minimumRating === 1} onClick={() => { setMinimumRating(minimumRating === 1 ? 0 : 1); setFailedEmbeddingsOnly(false); }} />
-        <FilterPill label="4★+" active={minimumRating === 4} onClick={() => { setMinimumRating(minimumRating === 4 ? 0 : 4); setFailedEmbeddingsOnly(false); }} />
+        <FilterPill label="All" active={mediaFilter === "all" && !favoritesOnly && !failedEmbeddingsOnly && !failedTaggingOnly && minimumRating === 0} onClick={() => { setMediaFilter("all"); setFavoritesOnly(false); setMinimumRating(0); setFailedEmbeddingsOnly(false); setFailedTaggingOnly(false); }} />
+        <FilterPill label="Images" active={mediaFilter === "image" && !favoritesOnly && !failedEmbeddingsOnly && !failedTaggingOnly} onClick={() => { setMediaFilter("image"); setFavoritesOnly(false); setFailedEmbeddingsOnly(false); setFailedTaggingOnly(false); }} />
+        <FilterPill label="Videos" active={mediaFilter === "video" && !favoritesOnly && !failedEmbeddingsOnly && !failedTaggingOnly} onClick={() => { setMediaFilter("video"); setFavoritesOnly(false); setFailedEmbeddingsOnly(false); setFailedTaggingOnly(false); }} />
+        <FilterPill label="Favorites" active={favoritesOnly} onClick={() => { setFavoritesOnly(!favoritesOnly); setFailedEmbeddingsOnly(false); setFailedTaggingOnly(false); }} />
+        <FilterPill label="Rated" active={minimumRating === 1} onClick={() => { setMinimumRating(minimumRating === 1 ? 0 : 1); setFailedEmbeddingsOnly(false); setFailedTaggingOnly(false); }} />
+        <FilterPill label="4★+" active={minimumRating === 4} onClick={() => { setMinimumRating(minimumRating === 4 ? 0 : 4); setFailedEmbeddingsOnly(false); setFailedTaggingOnly(false); }} />
         <FilterPill label="Similar: Folder" active={similarScope === "current_folder"} onClick={() => setSimilarScope("current_folder")} />
         <FilterPill label="Similar: All" active={similarScope === "all_media"} onClick={() => setSimilarScope("all_media")} />
         {hasAnyFailedEmbeddings ? (
@@ -457,6 +460,14 @@ export function Toolbar() {
             onClick={() => setFailedEmbeddingsOnly(!failedEmbeddingsOnly)}
           />
         ) : null}
+        {hasAnyFailedTagging ? (
+          <FilterPill
+            label="Failed Tags"
+            active={failedTaggingOnly}
+            variant="amber"
+            onClick={() => setFailedTaggingOnly(!failedTaggingOnly)}
+          />
+        ) : null}
         {isSimilarResults ? <span className="ml-2 text-[11px] text-gray-500">Current similar scope: {similarScope === "current_folder" ? "current folder" : "all media"}</span> : null}
       </div>
     </div>