fix(desktop): persist composer drafts across reloads

Save in-progress composer text to browser localStorage per chat session and restore it when the desktop composer remounts. Keep the draft when submit is rejected or throws, and clear it only after the prompt is accepted.

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

@@ -24,7 +24,14 @@ import { desktopSlashCommandTakesArgs } from '@/lib/desktop-slash-commands'
 import { DATA_IMAGE_URL_RE } from '@/lib/embedded-images'
 import { triggerHaptic } from '@/lib/haptics'
 import { cn } from '@/lib/utils'
-import { $composerAttachments, clearComposerAttachments, type ComposerAttachment } from '@/store/composer'
+import {
+  $composerAttachments,
+  clearComposerAttachments,
+  clearPersistedComposerDraft,
+  type ComposerAttachment,
+  readPersistedComposerDraft,
+  writePersistedComposerDraft
+} from '@/store/composer'
 import {
   browseBackward,
   browseForward,
@@ -160,6 +167,7 @@ export function ChatBar({
   const scrolledUp = useStore($threadScrolledUp)
   const sessionMessages = useStore($messages)
   const activeQueueSessionKey = queueSessionKey || sessionId || null
+  const draftPersistenceScope = activeQueueSessionKey || null
 
   const queuedPrompts = useMemo(
     () => (activeQueueSessionKey ? (queuedPromptsBySession[activeQueueSessionKey] ?? []) : []),
@@ -171,6 +179,7 @@ export function ChatBar({
   const editorRef = useRef<HTMLDivElement | null>(null)
   const draftRef = useRef(draft)
   const previousBusyRef = useRef(busy)
+  const skipNextDraftPersistScopeRef = useRef<string | null>(null)
   const drainingQueueRef = useRef(false)
   const urlInputRef = useRef<HTMLInputElement | null>(null)
 
@@ -1097,6 +1106,22 @@ export function ChatBar({
     }
   }
 
+  useEffect(() => {
+    const persisted = readPersistedComposerDraft(draftPersistenceScope)
+    skipNextDraftPersistScopeRef.current = draftPersistenceScope
+    loadIntoComposer(persisted, [])
+  }, [draftPersistenceScope]) // eslint-disable-line react-hooks/exhaustive-deps
+
+  useEffect(() => {
+    if (skipNextDraftPersistScopeRef.current === draftPersistenceScope) {
+      skipNextDraftPersistScopeRef.current = null
+
+      return
+    }
+
+    writePersistedComposerDraft(draftPersistenceScope, draft)
+  }, [draft, draftPersistenceScope])
+
   const beginQueuedEdit = (entry: QueuedPromptEntry) => {
     if (!activeQueueSessionKey || queueEdit) {
       return
@@ -1323,8 +1348,10 @@ export function ChatBar({
     // input event; refresh it from the editor once more to also cover an
     // in-flight keystroke that hasn't fired its input event yet.
     const editor = editorRef.current
+
     if (editor) {
       const domText = composerPlainText(editor)
+
       if (domText !== draftRef.current) {
         draftRef.current = domText
         aui.composer().setText(domText)
@@ -1348,7 +1375,17 @@ export function ChatBar({
         const submitted = text
         triggerHaptic('submit')
         clearDraft()
-        void onSubmit(submitted)
+        void Promise.resolve(onSubmit(submitted)).then(accepted => {
+          if (accepted === false) {
+            loadIntoComposer(submitted, [])
+            writePersistedComposerDraft(draftPersistenceScope, submitted)
+          } else {
+            clearPersistedComposerDraft(draftPersistenceScope)
+          }
+        }).catch(() => {
+          loadIntoComposer(submitted, [])
+          writePersistedComposerDraft(draftPersistenceScope, submitted)
+        })
       } else if (payloadPresent) {
         queueCurrentDraft()
       } else {
@@ -1361,11 +1398,22 @@ export function ChatBar({
       void drainNextQueued()
     } else if (payloadPresent) {
       const submitted = text
+      const submittedAttachments = cloneAttachments(attachments)
       triggerHaptic('submit')
       resetBrowseState(sessionId)
       clearDraft()
       clearComposerAttachments()
-      void onSubmit(submitted, { attachments })
+      void Promise.resolve(onSubmit(submitted, { attachments: submittedAttachments })).then(accepted => {
+        if (accepted === false) {
+          loadIntoComposer(submitted, submittedAttachments)
+          writePersistedComposerDraft(draftPersistenceScope, submitted)
+        } else {
+          clearPersistedComposerDraft(draftPersistenceScope)
+        }
+      }).catch(() => {
+        loadIntoComposer(submitted, submittedAttachments)
+        writePersistedComposerDraft(draftPersistenceScope, submitted)
+      })
     }
 
     focusInput()