feat(gui,fuse,core): share photos, copy image, thumbnail strip in the viewer

- Share… in the grid's photo menu and the viewer's ⋮ menu opens the Share
  dialog by uid. The daemon accepts a uid from the Photos timeline for
  sharing (resolve_shareable), since the photos volume is in no mount.
  Photos in an album someone else shared are not offered.
- Copy Image (Ctrl+C) puts the shown still on the clipboard. The viewer
  has its own toast overlay, so this and Save a Copy confirm over it
  instead of behind it.
- A thumbnail strip along the viewer's bottom edge, on the gallery model,
  marks the shown photo and jumps on click. Several pictures can now
  wait for one thumbnail, so the strip and the grid tile don't steal it
  from each other.
- PhotoItem carries place_id (serde default); the line under the
  viewer's title reads "Berlin · 12 of 340".

crates/pdfs-core/src/control.rs

@@ -1792,6 +1792,11 @@ pub struct PhotoItem {
     /// the JPEG it shows is not the whole of what is stored.
     #[serde(default)]
     pub has_raw: bool,
+    /// GeoNames id of the town the photo was taken in, when its location is
+    /// known; [`crate::places::city`] names it. Older daemons omit it, and
+    /// album entries do not carry it.
+    #[serde(default)]
+    pub place_id: Option<u32>,
 }
 
 /// A daemon too old to classify a timeline entry is assumed to have served a