perf(desktop): retain channel page provenance with warm rows

Keep the authoritative channel window alive for the same hour as its
projected message cache so revisits cannot lose loader provenance first.

Co-authored-by: Carl <c7ebe626f000404285d3686e1dc74cc07cc60a9754a150041ba132e14bd3e2ec@buzz.block.builderlab.xyz>
Signed-off-by: Wes <wesbillman@users.noreply.github.com>

desktop/src/features/messages/hooks.ts

@@ -228,6 +228,8 @@ export function resolveThreadReplyTarget(
   };
 }
 
+export const CHANNEL_TIMELINE_GC_TIME_MS = 60 * 60 * 1_000;
+
 export function useChannelWindowQuery(channel: Channel | null) {
   const queryClient = useQueryClient();
   const queryKey = channelWindowKey(channel?.id ?? "none");
@@ -238,6 +240,9 @@ export function useChannelWindowQuery(channel: Channel | null) {
       queryClient.getQueryData<ChannelWindowStore>(queryKey) ??
       emptyChannelWindowStore(),
     staleTime: Number.POSITIVE_INFINITY,
+    // Page provenance determines whether cached rows (including known-empty)
+    // are warm enough to paint. Retain it for exactly as long as those rows.
+    gcTime: CHANNEL_TIMELINE_GC_TIME_MS,
   });
 }
 
@@ -368,7 +373,7 @@ export function useChannelMessagesQuery(channel: Channel | null) {
       );
     },
     staleTime: 5 * 60 * 1_000,
-    gcTime: 60 * 60 * 1_000,
+    gcTime: CHANNEL_TIMELINE_GC_TIME_MS,
   });
 }
 

desktop/src/features/messages/lib/projectChannelWindow.test.mjs

@@ -3,6 +3,7 @@ import test from "node:test";
 import { QueryClient, QueryObserver } from "@tanstack/react-query";
 
 import {
+  CHANNEL_TIMELINE_GC_TIME_MS,
   reconcileFetchedChannelWindow,
   reconcileFetchedChannelWindowPages,
 } from "../hooks.ts";
@@ -54,6 +55,10 @@ function newestPage(rows) {
   };
 }
 
+test("channel page provenance is retained for the full warm-row lifetime", () => {
+  assert.equal(CHANNEL_TIMELINE_GC_TIME_MS, 60 * 60 * 1_000);
+});
+
 function createHarness() {
   const client = new QueryClient({
     defaultOptions: { queries: { retry: false } },