feat(share): dup-aware interactive save card with AI tag suggestions

Replace the fire-and-forget share toast with an interactive SwiftUI card.
On open it checks linkding's /api/bookmarks/check/ so an already-saved URL
routes to an Update (no more silent duplicates) and a new URL shows a save
form with title, tags, notes, and a read-later toggle.

Tag suggestions are hybrid: fetch the user's existing tag vocabulary
(/api/tags/) and AI tag ideas (/v1/marks/enrich via anonymous device auth),
auto-fill known-vocabulary matches into the field and surface net-new ideas
as tappable chips. Best-effort and non-blocking — failures never block save.

Also:
- Refresh bookmarks when the app returns to the foreground (scenePhase).
- Render bookmark dates as a static relative label instead of the live
  ticking RelativeDateTime timer.
- Share LinkdingAPI/Bookmark/ServerConfig/MarksAuth into the ShareExtension
  target via project.yml (durable across xcodegen regen) and regenerate.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

project.yml

@@ -83,6 +83,12 @@ targets:
     platform: iOS
     sources:
       - path: ShareExtension
+      # Shared with the main app so the extension can talk to linkding + the AI
+      # backend (the save card checks for duplicates and suggests tags).
+      - path: Marks/Models/Bookmark.swift
+      - path: Marks/Models/ServerConfig.swift
+      - path: Marks/Services/LinkdingAPI.swift
+      - path: Marks/Services/MarksAuth.swift
     settings:
       base:
         PRODUCT_BUNDLE_IDENTIFIER: com.magicive.marks.ShareExtension