Merge branch 'perf/lag': dashboard lag fixes

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

# Conflicts:
#	client/src/components/Sagi/PetSprite.tsx
#	client/src/components/Sagi/useSagiBrain.ts

client/src/components/Sagi/useSagiBrain.ts

@@ -90,6 +90,17 @@ import { greetingKey, pickLine, pickQuip } from "./quips";
 import { statusSummary } from "./intents";
 import { sagiPrefs } from "./prefs";
 
+/** `next` differs from `prev` only by a lastActivityAt less than a second
+ *  newer — nothing the mascot shows, at the moods' 1 s resolution. */
+function onlyActivityMoved(prev: SagiState, next: SagiState): boolean {
+  if (next === prev) return true;
+  if (next.lastActivityAt - prev.lastActivityAt >= 1000) return false;
+  for (const k of Object.keys(next) as (keyof SagiState)[]) {
+    if (k !== "lastActivityAt" && next[k] !== prev[k]) return false;
+  }
+  return true;
+}
+
 const BUBBLE_MS = 4500;
 // A bubble that names a session stays long enough to click it.
 const SUBJECT_BUBBLE_MS = 7000;
@@ -283,8 +294,12 @@ export function useSagiBrain(): SagiBrain {
   // Subscribe to the live stream and connection status.
   useEffect(() => {
     const unsubMsg = eventBus.subscribe((msg: WSMessage) => {
-      const { state: next, pulse, subject } = reduceSagi(stateRef.current, msg, Date.now());
-      update(() => next);
+      const prev = stateRef.current;
+      const { state: next, pulse, subject } = reduceSagi(prev, msg, Date.now());
+      // Most frames only move lastActivityAt, which the moods read at a 1 s
+      // resolution: keep the old state then, so a hook burst (several frames a
+      // second) does not re-render the mascot on every frame.
+      if (!onlyActivityMoved(prev, next)) update(() => next);
       if (pulse) notify(pulse, subject);
     });
     const unsubConn = eventBus.onConnection((connected) => {
@@ -300,8 +315,12 @@ export function useSagiBrain(): SagiBrain {
   // happy/worried) re-evaluate without needing a new event.
   useEffect(() => {
     // Hidden tab: no re-render; the first visible tick catches the mood up.
+    // Only a tick that changes the mood re-renders: an idle mascot is not
+    // drawn again every second for nothing.
     const id = setInterval(() => {
-      if (document.visibilityState === "visible") setTick(Date.now());
+      if (document.visibilityState !== "visible") return;
+      const now = Date.now();
+      if (deriveMood(stateRef.current, now) !== moodRef.current) setTick(now);
     }, 1000);
     return () => clearInterval(id);
   }, []);
@@ -315,7 +334,9 @@ export function useSagiBrain(): SagiBrain {
     []
   );
 
-  const mood = useMemo(() => deriveMood(state, tick), [state, tick]);
+  // Judged at render time: `tick` only moves when the mood would change, so
+  // it may be old when a frame re-renders.
+  const mood = useMemo(() => deriveMood(state, Math.max(tick, Date.now())), [state, tick]);
   const status = useMemo(() => statusOf(state), [state]);
   const attention = useMemo(() => attentionOf(state), [state]);