ui: tighten dashboard copy and fix layout issues

lib/cache.ts

@@ -18,6 +18,11 @@ interface CacheEntry<T> {
   data: T
   ts: number
   revalidating: boolean
+  /** onUpdate callbacks of every caller that hit this key while a background
+   *  revalidation was in flight (M9 fix). All are notified when the fetch
+   *  resolves — previously only the caller that STARTED the revalidation got
+   *  fresh data; everyone else silently kept the stale copy. */
+  subscribers: Array<(fresh: T) => void>
 }
 
 const store = new Map<string, CacheEntry<unknown>>()
@@ -37,16 +42,22 @@ export async function swrFetch<T>(
       // Still fresh — return immediately.
       return hit.data
     }
-    // Stale — return immediately AND revalidate in background.
+    // Stale — return immediately AND revalidate in background. Every caller's
+    // onUpdate joins the subscriber list; the in-flight fetch notifies all.
+    if (onUpdate) hit.subscribers.push(onUpdate)
     if (!hit.revalidating) {
       hit.revalidating = true
       fetcher()
         .then(fresh => {
-          store.set(key, { data: fresh, ts: Date.now(), revalidating: false })
-          onUpdate?.(fresh)
+          const subs = hit.subscribers
+          store.set(key, { data: fresh, ts: Date.now(), revalidating: false, subscribers: [] })
+          for (const notify of subs) {
+            try { notify(fresh) } catch { /* one bad subscriber must not starve the rest */ }
+          }
         })
         .catch(() => {
-          if (hit) hit.revalidating = false
+          hit.revalidating = false
+          hit.subscribers = []
         })
     }
     return hit.data
@@ -54,7 +65,7 @@ export async function swrFetch<T>(
 
   // Cache miss — must wait for the first fetch.
   const data = await fetcher()
-  store.set(key, { data, ts: Date.now(), revalidating: false })
+  store.set(key, { data, ts: Date.now(), revalidating: false, subscribers: [] })
   return data
 }