fix(21-05): move PlanTasksFetcher onTasks callback to useEffect

Replace the setState-during-render pattern in PlanTasksFetcher with a
useEffect hook. The onTasks callback was being called directly in the
render body when tasksQuery.isSuccess was true, which could cause
infinite re-render loops when the parent state update triggered a
re-render. Now data flows through useEffect with proper dependencies.

packages/web/src/routes/initiatives/$id.tsx

@@ -1,4 +1,4 @@
-import { useState, useCallback } from "react";
+import { useState, useCallback, useEffect } from "react";
 import { createFileRoute, useNavigate } from "@tanstack/react-router";
 import { AlertCircle } from "lucide-react";
 import { Button } from "@/components/ui/button";
@@ -193,12 +193,13 @@ interface PlanTasksFetcherProps {
 function PlanTasksFetcher({ planId, onTasks }: PlanTasksFetcherProps) {
   const tasksQuery = trpc.listTasks.useQuery({ planId });
 
-  // Report tasks upward when loaded
-  if (tasksQuery.isSuccess && tasksQuery.data) {
-    // Cast to SerializedTask — tRPC serializes Date to string over JSON
-    const tasks = tasksQuery.data as unknown as SerializedTask[];
-    onTasks(planId, tasks);
+  // Report tasks upward via useEffect (not during render) to avoid
+  // setState-during-render loops when the parent re-renders on state update.
+  useEffect(() => {
+    if (tasksQuery.data) {
+      onTasks(planId, tasksQuery.data as unknown as SerializedTask[]);
     }
+  }, [tasksQuery.data, planId, onTasks]);
 
   return null; // Render nothing — this is a data-fetching component
 }