fix(beszel): harden cache layer and prevent blank widgets (#6052)

* fix(beszel): harden cache layer and prevent blank widgets

- Add debug logging across Beszel integration, request handler, and tRPC
  router (auth, fetch, SSE, per-procedure entry/exit) gated behind
  LOG_LEVEL=debug
- cached-request-handler: retry with backoff, isValid predicate to skip
  caching invalid data, in-flight dedup (single-flight per channel) to
  avoid thundering herd after cache invalidation
- redis channel: set-then-publish so storage is always consistent even
  when pubsub publish fails
- Beszel handlers: opt into fallbackToStaleOnError and retry so brief
  upstream hiccups don't throw away good cached data
- beszel-system-stats: add refetchInterval matching each time period's
  cache TTL so historical charts refresh in the background
- tRPC router: switch Promise.all -> Promise.allSettled for getSystems
  and getAlerts; getSystemStats returns an error object instead of
  throwing. Each result carries an optional error field so one failed
  integration no longer nukes the whole widget
- Widgets: add explicit isPending loader, empty state for grid and
  stats, and a shared per-integration error indicator (tooltip with
  failed integration names). Alerts and table now only show their
  empty state after loading completes
- Translation: add empty.noSystems key to beszelSystemGrid and
  beszelSystemStats

Addresses #6030

* style: auto-fix lint and format

---------

Co-authored-by: ajnart <ajnart@users.noreply.github.com>

packages/redis/src/lib/channel.ts

@@ -415,8 +415,18 @@ export const createChannelWithLatestAndEvents = <TData>(channelName: string) =>
       });
     },
     publishAndUpdateLastStateAsync: async (data: TData) => {
-      await publisher.publish(channelName, superjson.stringify(data));
-      await getSetClient.set(channelName, superjson.stringify({ data, timestamp: new Date() }));
+      // Set first, then publish. If publish fails the storage is still consistent
+      // and subscribers will catch up on the next event.
+      const payload = superjson.stringify({ data, timestamp: new Date() });
+      await getSetClient.set(channelName, payload);
+      try {
+        await publisher.publish(channelName, superjson.stringify(data));
+      } catch (error) {
+        logger.warn("Failed to publish cache update (storage is correct, subscribers will catch up)", {
+          channel: channelName,
+          error: error instanceof Error ? error.message : String(error),
+        });
+      }
     },
     setAsync: async (data: TData) => {
       await getSetClient.set(channelName, superjson.stringify({ data, timestamp: new Date() }));