Upstream removed sora feature (090_drop_sora.sql) but left i18n keys
and wire.go references. Clean up:
- Remove entire sora i18n block from en.ts and zh.ts (~190 lines)
- Remove sora nav key and unused 'data' settings tab key
- Remove sora_client_enabled from settings (fork-specific)
- Remove SoraMediaCleanupService from wire.go