refactor(orders): replace local state machine with minimal cache

Strip store/orders.ts to a thin local cache with setOrders and
updateOrder only. Remove all client-side state transition logic,
actor validation, chat sync, notification generation, and wallet
integration — these are now handled by the backend API.

Fix components/order-actions.tsx and stores that depended on
the removed order store methods (markDisputed, autoTimeout*).

app/(order)/order/[id]/page.tsx

@@ -5,9 +5,10 @@ import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card"
 import { EmptyState } from "@/components/ui/empty-state"
 import { Separator } from "@/components/ui/separator"
 import { StatusBadge } from "@/components/ui/status-badge"
-import { getOrderById, listChatSessions, listReviewsByOrder } from "@/lib/api"
+import { getOrderById, getPlayerById, getUserById, listReviewsByOrder } from "@/lib/api"
 import { statusLabels } from "@/lib/constants"
-import type { OrderStatus } from "@/lib/types"
+import type { OrderStatus, Player, User } from "@/lib/types"
+import { useAuthStore } from "@/store/auth"
 import { ArrowLeft, CheckCircle, Clock, Star } from "lucide-react"
 import Link from "next/link"
 import { use, useEffect, useState } from "react"
@@ -46,32 +47,15 @@ const statusVariants: Record<OrderStatus, OrderStatusBadgeVariant> = {
 
 export default function OrderDetailPage({ params }: { params: Promise<{ id: string }> }) {
   const { id } = use(params)
-  const [sessions, setSessions] = useState<Awaited<ReturnType<typeof listChatSessions>>>([])
+  const currentUserId = useAuthStore((state) => state.user?.id)
   const [reviews, setReviews] = useState<Awaited<ReturnType<typeof listReviewsByOrder>>>([])
+  const [chatTarget, setChatTarget] = useState<User | null>(null)
+  const [player, setPlayer] = useState<Player | null>(null)
   const [order, setOrder] = useState<Awaited<ReturnType<typeof getOrderById>> | undefined>(
     undefined,
   )
   const [loading, setLoading] = useState(true)
 
-  useEffect(() => {
-    let cancelled = false
-
-    void (async () => {
-      try {
-        const sessions = await Promise.resolve(listChatSessions())
-        if (cancelled) return
-        setSessions(sessions)
-      } catch {
-        if (cancelled) return
-        setSessions([])
-      }
-    })()
-
-    return () => {
-      cancelled = true
-    }
-  }, [])
-
   useEffect(() => {
     let cancelled = false
 
@@ -94,6 +78,42 @@ export default function OrderDetailPage({ params }: { params: Promise<{ id: stri
     }
   }, [id])
 
+  useEffect(() => {
+    let cancelled = false
+
+    void (async () => {
+      if (!order || !currentUserId) {
+        setPlayer(null)
+        setChatTarget(null)
+        return
+      }
+
+      try {
+        setPlayer(null)
+        setChatTarget(null)
+        const player = await getPlayerById(String(order.playerId))
+        if (!cancelled) setPlayer(player ?? null)
+
+        if (String(order.consumerId) === currentUserId) {
+          if (!cancelled) setChatTarget(player?.user ?? null)
+          return
+        }
+
+        if (player?.user.id === currentUserId) {
+          const consumer = await getUserById(String(order.consumerId))
+          if (!cancelled) setChatTarget(consumer ?? null)
+        }
+      } catch {
+        if (!cancelled) setPlayer(null)
+        if (!cancelled) setChatTarget(null)
+      }
+    })()
+
+    return () => {
+      cancelled = true
+    }
+  }, [currentUserId, order])
+
   useEffect(() => {
     let cancelled = false
 
@@ -129,7 +149,6 @@ export default function OrderDetailPage({ params }: { params: Promise<{ id: stri
     )
   }
 
-  const chatSession = sessions.find((session) => session.type === "order" && session.orderId === id)
   const statusSteps =
     order.status === "disputed"
       ? disputedStatusSteps
@@ -137,6 +156,7 @@ export default function OrderDetailPage({ params }: { params: Promise<{ id: stri
         ? cancelledStatusSteps
         : normalStatusSteps
   const currentStepIndex = statusSteps.indexOf(order.status)
+  const isPlayerParticipant = player?.user.id === currentUserId
 
   return (
     <div className="container mx-auto py-8 px-4 max-w-2xl">
@@ -291,7 +311,8 @@ export default function OrderDetailPage({ params }: { params: Promise<{ id: stri
         order={order}
         onOrderChange={(next) => setOrder(next)}
         initialStatus={order.status}
-        chatSessionId={chatSession?.id}
+        chatTargetId={chatTarget?.id}
+        isPlayerParticipant={isPlayerParticipant}
         serviceId={order.service.id}
       />
     </div>