Add preview image picker to extension Save Link pane

New: "Unsorted" — save first, organize later
- Links now save to your Unsorted group by default, so you can save with one click and sort them into groups later in Zeerka.
- The destination picker is redesigned: Unsorted and your favorite groups appear as one-click chips right in the popup. Use "Change" to pick any other group.
- You no longer need to create a tab in Zeerka before saving your first link.
- Your last-used destination is remembered until you close the browser. After that, saving starts from Unsorted again.
- If the group you picked has been deleted, saving falls back to Unsorted.
- The confirmation message now shows where the link was saved.

Fixed SVG inline data favicons.

Improved handling of saving icons, including SVG icons.

Automatic favicon capturing when saving a link.

Security and privacy hardening. No new permissions and no new features.

Fixes

• Stellar Search now waits for your Zeerka data to finish loading before it
runs. Previously, when no Zeerka tab was open and Stellar Search opened one
for you, it could come up with no results and an empty row of search-provider
shortcuts — and pressing Enter wouldn't start a search.