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/20260409120500_add_client_update_policies.sql

@@ -0,0 +1,11 @@
+drop policy if exists "Client updates own company" on public.companies;
+create policy "Client updates own company" on public.companies
+  for update
+  using (id = get_my_company_id())
+  with check (id = get_my_company_id());
+
+drop policy if exists "Client updates own company projects" on public.projects;
+create policy "Client updates own company projects" on public.projects
+  for update
+  using (company_id = get_my_company_id())
+  with check (company_id = get_my_company_id());