docs(32): fix wave assignment — Plan 04 bumped to wave 4

Plans 03 and 04 both modify setups/$setupId.tsx. Per wave assignment
rules, file overlap requires sequential execution. Plan 04 now depends
on Plan 03 and runs in Wave 4.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.planning/phases/32-setup-sharing-system/32-04-PLAN.md

@@ -2,8 +2,8 @@
 phase: 32-setup-sharing-system
 plan: 04
 type: execute
-wave: 3
-depends_on: [01, 02]
+wave: 4
+depends_on: [01, 02, 03]
 files_modified:
   - src/client/routes/setups/$setupId.tsx
   - src/client/hooks/useSetups.ts