feat(workspace): trash for notes

Deleting a note (or its folder) moves it to the trash instead of erasing
it. Trashed notes leave the tree, search, export and stats and are hidden
from everyone they were shared with; the owner sees them read-only with a
restore banner. New endpoints list, restore, purge and empty the trash;
restoring recreates a deleted folder. Sidebar entry and mobile menu item
with counter, list view with two-tap permanent delete.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/storage/docsync.go

@@ -549,14 +549,22 @@ func (s *Store) DocRole(userID, docID string) string {
 	if userID == "" {
 		return ""
 	}
-	var ownerID, sharedFolderID, folderOwner string
+	var ownerID, sharedFolderID, folderOwner, archivedBy string
+	var archived bool
 	err := s.db.QueryRow(
-		`SELECT d.user_id, d.shared_folder_id, COALESCE(wsf.owner_id, '')
+		`SELECT d.user_id, d.shared_folder_id, COALESCE(wsf.owner_id, ''), d.is_archived, d.archived_by
 		 FROM documents d LEFT JOIN workspace_shared_folders wsf ON wsf.id = d.shared_folder_id
-		 WHERE d.id = ?`, docID).Scan(&ownerID, &sharedFolderID, &folderOwner)
+		 WHERE d.id = ?`, docID).Scan(&ownerID, &sharedFolderID, &folderOwner, &archived, &archivedBy)
 	if err != nil {
 		return ""
 	}
+	if archived {
+		// In the trash: read-only for the owner and whoever trashed it, hidden from everyone else
+		if ownerID == userID || archivedBy == userID {
+			return DocRoleViewer
+		}
+		return ""
+	}
 	if ownerID == userID {
 		return DocRoleOwner
 	}