fix(app): file tree not always loading

packages/app/src/pages/session.tsx

@@ -1256,7 +1256,33 @@ export default function Page() {
     if (!wants) return
     if (sync.data.session_diff[id] !== undefined) return
 
-    sync.session.diff(id)
+    const state = {
+      cancelled: false,
+      attempt: 0,
+      timer: undefined as number | undefined,
+    }
+
+    const load = () => {
+      if (state.cancelled) return
+      const pending = sync.session.diff(id)
+      if (!pending) return
+      pending.catch(() => {
+        if (state.cancelled) return
+        const attempt = state.attempt + 1
+        state.attempt = attempt
+        if (attempt > 5) return
+        if (state.timer !== undefined) clearTimeout(state.timer)
+        const wait = Math.min(10000, 250 * 2 ** (attempt - 1))
+        state.timer = window.setTimeout(load, wait)
+      })
+    }
+
+    load()
+
+    onCleanup(() => {
+      state.cancelled = true
+      if (state.timer !== undefined) clearTimeout(state.timer)
+    })
   })
 
   const autoScroll = createAutoScroll({