Fix file sharing load speed and move error; misc updates

- Remove recursive directory size calculations (single Seafile API call per list)
- Remove 'Used in this location' usage display
- Fix move using v2 per-type endpoints instead of broken batch endpoint
- Send entry type from frontend for correct move routing

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

supabase/migrations/20260513120000_client_task_delete_policy.sql

@@ -0,0 +1,20 @@
+-- Allow clients to delete tasks in their own company's projects.
+-- Previously only team members could delete tasks (no client delete policy existed),
+-- so client-side "Delete Request" silently failed with 0 rows deleted.
+
+drop policy if exists "Client deletes company tasks" on public.tasks;
+create policy "Client deletes company tasks" on public.tasks
+  for delete using (
+    get_my_role() = 'client'
+    and project_id in (
+      select id from public.projects where has_company_access(company_id)
+    )
+  );
+
+-- Also allow clients to delete projects (needed when the last task in a project is deleted).
+drop policy if exists "Client deletes company projects" on public.projects;
+create policy "Client deletes company projects" on public.projects
+  for delete using (
+    get_my_role() = 'client'
+    and has_company_access(company_id)
+  );