Reduce unnecessary re-renders in agent panel and input components

Narrow zustand selectors to only subscribe to fields each component
actually uses. Split nested objects (availableModes, projectPlacement)
into separate selectors with structural equality checks. Remove the
updatedAt processing-spinner hack in agent-input-area — the server
already guarantees agent status is "running" before ACKing the send
request, so isProcessing can clear on submit success directly.

packages/app/src/components/agent-input-area.tsx

@@ -1,6 +1,7 @@
 import { View, Pressable, Text, ActivityIndicator, Platform } from "react-native";
 import { useState, useEffect, useRef, useCallback } from "react";
 import { StyleSheet, UnistylesRuntime, useUnistyles } from "react-native-unistyles";
+import { useShallow } from "zustand/shallow";
 import { ArrowUp, Square, Pencil, AudioLines } from "lucide-react-native";
 import Animated from "react-native-reanimated";
 import { useSafeAreaInsets } from "react-native-safe-area-context";
@@ -126,7 +127,14 @@ export function AgentInputArea({
       agentDirectoryStatus === "revalidating" ||
       agentDirectoryStatus === "error_after_ready");
 
-  const agent = useSessionStore((state) => state.sessions[serverId]?.agents?.get(agentId));
+  const agentState = useSessionStore(
+    useShallow((state) => {
+      const agent = state.sessions[serverId]?.agents?.get(agentId) ?? null;
+      return {
+        status: agent?.status ?? null,
+      };
+    }),
+  );
 
   const queuedMessagesRaw = useSessionStore((state) =>
     state.sessions[serverId]?.queuedMessages?.get(agentId),
@@ -272,41 +280,8 @@ export function AgentInputArea({
     onSubmitMessageRef.current = onSubmitMessage;
   }, [onSubmitMessage]);
 
-  const isAgentRunning = agent?.status === "running";
-  const agentUpdatedAtMs = agent?.updatedAt?.getTime() ?? 0;
-
-  const prevIsAgentRunningRef = useRef(isAgentRunning);
-  const latestAgentUpdatedAtRef = useRef(agentUpdatedAtMs);
-  useEffect(() => {
-    const previousUpdatedAt = latestAgentUpdatedAtRef.current;
-    if (agentUpdatedAtMs < previousUpdatedAt) {
-      if (isProcessing && !isAgentRunning) {
-        prevIsAgentRunningRef.current = false;
-        setIsProcessing(false);
-      }
-      return;
-    }
-
-    const wasRunning = prevIsAgentRunningRef.current;
-    let shouldClearProcessing = false;
-
-    if (isProcessing) {
-      const hasEnteredRunning = !wasRunning && isAgentRunning;
-      const hasFreshRunningUpdateWhileRunning =
-        wasRunning && isAgentRunning && agentUpdatedAtMs > previousUpdatedAt;
-      const hasStoppedRunning = wasRunning && !isAgentRunning;
-
-      shouldClearProcessing =
-        hasEnteredRunning || hasFreshRunningUpdateWhileRunning || hasStoppedRunning;
-    }
-
-    prevIsAgentRunningRef.current = isAgentRunning;
-    latestAgentUpdatedAtRef.current = agentUpdatedAtMs;
-
-    if (shouldClearProcessing) {
-      setIsProcessing(false);
-    }
-  }, [agentUpdatedAtMs, isAgentRunning, isProcessing]);
+  const isAgentRunning = agentState.status === "running";
+  const hasAgent = agentState.status !== null;
 
   const updateQueue = useCallback(
     (updater: (current: QueuedMessage[]) => QueuedMessage[]) => {
@@ -348,7 +323,7 @@ export function AgentInputArea({
       message,
       imageAttachments,
       forceSend,
-      isAgentRunning: agent?.status === "running",
+      isAgentRunning: agentState.status === "running",
       // Parent-managed submits are still valid submit paths even when the
       // transport is disconnected, because the parent decides the failure mode.
       canSubmit: Boolean(sendAgentMessageRef.current || onSubmitMessageRef.current),
@@ -481,7 +456,7 @@ export function AgentInputArea({
   });
 
   function handleCancelAgent() {
-    if (!agent || agent.status !== "running" || isCancellingAgent) {
+    if (!isAgentRunning || isCancellingAgent) {
       return;
     }
     if (!isConnected || !client) {
@@ -495,7 +470,7 @@ export function AgentInputArea({
   const isVoiceModeForAgent = voice?.isVoiceModeForAgent(serverId, agentId) ?? false;
 
   const handleToggleRealtimeVoice = useCallback(() => {
-    if (!voice || !isConnected || !agent) {
+    if (!voice || !isConnected || !hasAgent) {
       return;
     }
     if (voice.isVoiceSwitching) {
@@ -512,7 +487,7 @@ export function AgentInputArea({
         toast.error(message);
       }
     });
-  }, [agent, agentId, isConnected, serverId, toast, voice]);
+  }, [agentId, hasAgent, isConnected, serverId, toast, voice]);
 
   function handleEditQueuedMessage(id: string) {
     const item = queuedMessages.find((q) => q.id === id);
@@ -604,7 +579,7 @@ export function AgentInputArea({
 
   const rightContent = (
     <View style={styles.rightControls}>
-      {!isVoiceModeForAgent && agent ? (
+      {!isVoiceModeForAgent && hasAgent ? (
         <Tooltip delayDuration={0} enabledOnDesktop enabledOnMobile={false}>
           <TooltipTrigger
             onPress={handleToggleRealtimeVoice}