feat(ui): streamline workspace settings and remove sharing

Unify compact workspace controls and panel transitions, move directory actions into the context menu, and remove backlink UI.

Reorganize settings with searchable sections, per-setting resets, shortcut search, and accurate save feedback.

Remove sharing UI, APIs, authentication helpers, and storage code; provide a transactional cleanup script with retirement tests. Reject directories during orphan image cleanup and cover mixed-batch preservation.

internal/api/assets.go

@@ -1,11 +1,6 @@
 package api
 
-import (
-	"errors"
-	"net/http"
-	"rawmark/internal/vault"
-	"time"
-)
+import "net/http"
 
 func (s *Server) cleanupImages(w http.ResponseWriter, r *http.Request) {
 	var body struct {
@@ -18,28 +13,7 @@ func (s *Server) cleanupImages(w http.ResponseWriter, r *http.Request) {
 		writeError(w, 400, "请选择 1～1000 张待清理图片")
 		return
 	}
-	result, err := s.vault.CleanupImages(body.Paths, func() ([]string, error) {
-		shares, err := s.store.Shares()
-		if err != nil {
-			return nil, err
-		}
-		scopes := []string{}
-		now := time.Now().UnixMilli()
-		for _, share := range shares {
-			if share.ExpiresAt != 0 && share.ExpiresAt <= now {
-				continue
-			}
-			for _, item := range share.Items {
-				if _, err := s.vault.Stat(item.Path); errors.Is(err, vault.ErrNotFound) {
-					continue
-				} else if err != nil {
-					return nil, err
-				}
-				scopes = append(scopes, item.Path)
-			}
-		}
-		return scopes, nil
-	})
+	result, err := s.vault.CleanupImages(body.Paths)
 	if err != nil {
 		vaultError(w, r, err)
 		return