Fix plugin cloud sync: wire CloudSyncInvalidationBus to PluginManager

[test01203]

Bug

PluginManager.triggerRemoteSync() always returned early due to dead code left from the old Supabase auth system:

if (true /* !authManager.isAuthenticated */) {
    return  // ← always exits here, nothing is ever pushed
}

As a result, adding/removing plugin repositories was saved locally only and never triggered a cloud push.

Fix

3 files changed:

1. CloudSyncInvalidationBus.kt

Add PLUGINS to the CloudSyncScope enum so the coordinator knows how to debounce plugin changes.

2. CloudSyncCoordinator.kt

Add 1000ms debounce for PLUGINS scope (between IPTV's 750ms and LOCAL_HISTORY's 2000ms).

3. PluginManager.kt (sideload)

• Inject CloudSyncInvalidationBus
• Replace dead triggerRemoteSync() implementation with invalidationBus.markDirty(CloudSyncScope.PLUGINS, ...)
• Wire markDirty() to: addRepository, removeRepository, toggleScraper, toggleAllScrapersForRepo, setPluginsEnabled, flushPendingSync

Result

After this fix, any plugin change (add repo, remove repo, enable/disable scraper) will:

1. Save locally as before
2. Trigger CloudSyncCoordinator via the invalidation bus (1s debounce)
3. Push the full snapshot (including pluginRepositories + pluginScrapers) to cloud
4. Other devices sync down on next pull