fix(desktop): make draft persistence actually fire — new-chat sentinel, reload flush, session-switch clears

Manual testing of the salvaged draft persistence showed none of it worked
end-to-end. Three distinct bugs, all invisible to the store-level unit
tests:

1. New-chat drafts were never written. The skip-one-persist sentinel was
   reset to null after consuming, but null IS a real scope (the unsaved
   new-session draft) — so in a new chat every persist run matched the
   "consumed" sentinel and bailed. This silently killed the headline
   #38498 fix. Use undefined as the no-skip sentinel, which can never
   collide with a scope.

2. Cmd+R inside the debounce window dropped the trailing text. React does
   not run effect cleanups on a page reload, so the flush-on-unmount
   never fired; with the 400ms debounce that meant type-then-reload lost
   the draft every time. Flush pending writes on pagehide.

3. Session switch/new/resume/branch paths in use-session-actions cleared
   the composer stores synchronously with the session-id updates. React
   batches those, so by the time ChatBar's scope-change cleanup ran to
   stash the departing session's attachments, the store was already
   empty — the stash recorded [] and the chips were lost anyway. The
   composer's per-scope restore now owns composer contents wholesale on
   scope change, so drop the upstream clears (clearComposerDraft only
   touched the vestigial $composerDraft atom nothing reads).

Co-authored-by: mollusk <roger@roger.local>
Co-authored-by: Teknium <127238744+teknium1@users.noreply.github.com>

apps/desktop/src/app/chat/composer/index.tsx

@@ -186,7 +186,11 @@ export function ChatBar({
   const editorRef = useRef<HTMLDivElement | null>(null)
   const draftRef = useRef(draft)
   const previousBusyRef = useRef(busy)
-  const skipNextDraftPersistScopeRef = useRef<string | null>(null)
+  // `undefined` = no skip pending. The sentinel must be distinguishable from a
+  // real scope, and `null` IS a real scope (the unsaved-new-session draft):
+  // resetting to null made every persist run in a new chat match the consumed
+  // sentinel and bail, so new-chat drafts were never written at all.
+  const skipNextDraftPersistScopeRef = useRef<string | null | undefined>(undefined)
   const pendingDraftPersistRef = useRef<{ scope: string | null; value: string } | null>(null)
   const drainingQueueRef = useRef(false)
   const urlInputRef = useRef<HTMLInputElement | null>(null)
@@ -1132,7 +1136,7 @@ export function ChatBar({
 
   useEffect(() => {
     if (skipNextDraftPersistScopeRef.current === draftPersistenceScope) {
-      skipNextDraftPersistScopeRef.current = null
+      skipNextDraftPersistScopeRef.current = undefined
 
       return
     }
@@ -1161,19 +1165,28 @@ export function ChatBar({
     return () => window.clearTimeout(handle)
   }, [draft, draftPersistenceScope, queueEdit, sessionId])
 
-  // Flush any pending debounced draft write when leaving a session scope or
-  // unmounting, so the departing session's latest text is always persisted.
-  useEffect(
-    () => () => {
+  // Flush any pending debounced draft write when leaving a session scope,
+  // unmounting, or the window unloading, so the latest text is always
+  // persisted. The pagehide listener is load-bearing: React does NOT run
+  // effect cleanups on a page reload, so without it a Cmd+R inside the
+  // debounce window silently dropped everything typed in the last 400ms.
+  useEffect(() => {
+    const flushPendingDraftPersist = () => {
       const pending = pendingDraftPersistRef.current
 
       if (pending) {
         pendingDraftPersistRef.current = null
         writePersistedComposerDraft(pending.scope, pending.value)
       }
-    },
-    [draftPersistenceScope]
-  )
+    }
+
+    window.addEventListener('pagehide', flushPendingDraftPersist)
+
+    return () => {
+      window.removeEventListener('pagehide', flushPendingDraftPersist)
+      flushPendingDraftPersist()
+    }
+  }, [draftPersistenceScope])
 
   const beginQueuedEdit = (entry: QueuedPromptEntry) => {
     if (!activeQueueSessionKey || queueEdit) {

apps/desktop/src/app/session/hooks/use-session-actions.ts

@@ -8,7 +8,6 @@ import { type ChatMessage, chatMessageText, preserveLocalAssistantErrors, toChat
 import { normalizePersonalityValue } from '@/lib/chat-runtime'
 import { embeddedImageUrls, textWithoutEmbeddedImages } from '@/lib/embedded-images'
 import { setSessionYolo } from '@/lib/yolo-session'
-import { clearComposerAttachments, clearComposerDraft } from '@/store/composer'
 import { clearQueuedPrompts } from '@/store/composer-queue'
 import { $pinnedSessionIds } from '@/store/layout'
 import { clearNotifications, notify, notifyError } from '@/store/notifications'
@@ -19,7 +18,6 @@ import {
   $messages,
   $sessions,
   $yoloActive,
-  workspaceCwdForNewSession,
   sessionPinId,
   setActiveSessionId,
   setAwaitingResponse,
@@ -41,7 +39,8 @@ import {
   setSessionStartedAt,
   setSessionsTotal,
   setTurnStartedAt,
-  setYoloActive
+  setYoloActive,
+  workspaceCwdForNewSession
 } from '@/store/session'
 import { reportBackendContract } from '@/store/updates'
 import type { SessionCreateResponse, SessionInfo, SessionResumeResponse, UsageStats } from '@/types/hermes'
@@ -329,8 +328,10 @@ export function useSessionActions({
       setYoloActive(false)
       setCurrentCwd(workspaceCwdForNewSession())
       setCurrentBranch('')
-      clearComposerDraft()
-      clearComposerAttachments()
+      // Composer contents are owned by ChatBar's per-scope draft persistence:
+      // the scope change triggered by the session-id updates above stashes the
+      // departing session's attachments and restores this scope's draft.
+      // Clearing here would wipe the departing stash before it's saved.
       setFreshDraftReady(true)
     },
     [activeSessionIdRef, busyRef, navigate, selectedStoredSessionIdRef]
@@ -352,11 +353,13 @@ export function useSessionActions({
         // Pass the owning profile so a new chat under a non-launch profile (global
         // remote mode) builds its agent + persists against THAT profile's home/db.
         const newChatProfile = $newChatProfile.get()
+
         const created = await requestGateway<SessionCreateResponse>('session.create', {
           cols: 96,
           ...(cwd && { cwd }),
           ...(newChatProfile ? { profile: newChatProfile } : {})
         })
+
         const stored = created.stored_session_id ?? null
 
         if (
@@ -475,8 +478,6 @@ export function useSessionActions({
         setCurrentCwd(cachedState.cwd)
         setCurrentBranch(cachedState.branch)
         setSessionStartedAt(Date.now())
-        clearComposerDraft()
-        clearComposerAttachments()
 
         try {
           const usage = await requestGateway<UsageStats>('session.usage', { session_id: cachedRuntimeId })
@@ -606,8 +607,6 @@ export function useSessionActions({
           }),
           storedSessionId
         )
-        clearComposerDraft()
-        clearComposerAttachments()
       } catch (err) {
         if (!isCurrentResume()) {
           return
@@ -730,8 +729,6 @@ export function useSessionActions({
         selectedStoredSessionIdRef.current = routedSessionId
         navigate(sessionRoute(routedSessionId))
 
-        clearComposerDraft()
-        clearComposerAttachments()
         const runtimeInfo = applyRuntimeInfo(branched.info)
 
         patchSessionWorkspace(routedSessionId, runtimeInfo?.cwd)