feat(workspace): allow sharing notes and shared folders as editor

The share dialog for notes and shared folders now offers "Bearbeiten" and
"Nur Lesen" and stores write/read accordingly. Editors already edit through
the sync engine since phase 2.

Adds e2e/share.e2e.mjs: shares a note as editor through the dialog and checks
that the recipient can edit it; e2e/run.sh runs both browser tests.

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

frontend/src/features/workspace/WorkspaceView.tsx

@@ -2268,15 +2268,12 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
           shares={unifiedShares}
           teams={teams}
           collaborators={collaborators}
-          allowRoleSelection={false}
-          fixedPermission="viewer"
-          onAddShare={async (targetType, targetId) => {
+          onAddShare={async (targetType, targetId, role) => {
+            const permission = role === 'editor' ? 'write' : 'read';
             if (shareModalDoc) {
               await api.createDocShare(
                 shareModalDoc.id,
-                targetType === 'team'
-                  ? { teamId: targetId, permission: 'read' }
-                  : { userId: targetId, permission: 'read' }
+                targetType === 'team' ? { teamId: targetId, permission } : { userId: targetId, permission }
               );
               const updatedShares = await api.getDocShares(shareModalDoc.id);
               setActiveDocShares(updatedShares);
@@ -2284,7 +2281,7 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
               await api.createFolderShare(shareModalFolder.id, {
                 targetType,
                 targetId,
-                permission: 'read',
+                permission,
               });
               const updatedFolder = await api.getSharedFolder(shareModalFolder.id);
               setShareModalFolder(updatedFolder);