fix: pass visible sequence to openPreview from the click site

Previously the visible photo order was published only via a passive
useEffect on Timeline, which had a timing race: arrow nav in preview
could read a stale or empty sequence and fall back to the raw API
order, breaking visual order navigation in tag mode and after
filter changes.

Fix: openPreview now accepts an optional visibleSequence parameter,
and Timeline's onDoubleClick passes the freshly-computed flat
sequence directly. The store action adopts that sequence as the
authoritative visiblePhotoIds for the preview session, falling back
to the most-recently-published one for paths that don't have a click
site (e.g. the global Space hotkey).

The Timeline still publishes via useEffect for the Space-hotkey
fallback path, but the click path no longer depends on it.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/timeline/Timeline.tsx

@@ -297,20 +297,27 @@ export function Timeline() {
     [items]
   )
 
-  // Publish the flat visible-order id sequence to the photo store so
-  // PreviewView arrow nav (and the filmstrip) walks the same order the
-  // user sees in the grid. Includes duplicates from tag grouping —
-  // landing on the same photo's "second" appearance in the next tag
-  // bucket is the right behavior in tag mode.
-  useEffect(() => {
+  // Flat visible-order id sequence — exactly the order the user reads
+  // off the grid (top-to-bottom, left-to-right within each row).
+  // Includes duplicates from tag-grouping; landing on the same photo's
+  // "second" appearance in the next tag bucket is the right behavior
+  // in tag mode.
+  const visibleSequence = useMemo(() => {
     const ids: string[] = []
     for (const row of photoRows) {
       for (const cell of row.cells) {
         ids.push(cell.photo.id)
       }
     }
-    setVisiblePhotoIds(ids)
-  }, [photoRows, setVisiblePhotoIds])
+    return ids
+  }, [photoRows])
+
+  // Publish to the photo store so PreviewView's arrow nav and filmstrip
+  // can walk the same order even when opened from a non-click path
+  // (e.g. the global Space hotkey).
+  useEffect(() => {
+    setVisiblePhotoIds(visibleSequence)
+  }, [visibleSequence, setVisiblePhotoIds])
 
   // Locate the active photo in the visual grid. Returns the FIRST
   // (rowIndex, colIndex) where its id appears, since a tag-grouped view
@@ -518,7 +525,7 @@ export function Timeline() {
                           selectPhoto(photo.id, globalIndex)
                         }
                       }}
-                      onDoubleClick={() => openPreview(photo.id)}
+                      onDoubleClick={() => openPreview(photo.id, visibleSequence)}
                     />
                   ))}
                 </div>