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/20260409120300_restrict_profile_self_update.sql

@@ -0,0 +1,10 @@
+drop policy if exists "Own profile update" on public.profiles;
+
+create policy "Own profile update" on public.profiles
+  for update
+  using (id = auth.uid())
+  with check (
+    id = auth.uid()
+    and role = (select role from public.profiles where id = auth.uid())
+    and company_id is not distinct from (select company_id from public.profiles where id = auth.uid())
+  );