feat(desktop): integrate arrow history with the message queue

Builds on @naqerl's arrow up/down history (previous commit), making
ArrowUp do the right thing when a queue exists.

ArrowUp/ArrowDown priority:
1. Editing a queued turn → walk older/newer through queued entries,
   saving each edit; ArrowDown past the newest exits and restores the
   pre-edit draft.
2. Empty composer + queued turns → ArrowUp opens the newest queued entry
   for editing (the row's pencil), so Enter saves it back to the queue
   instead of firing a new message — the gap the history nav had alone.
3. Otherwise → sent-message history recall (unchanged).

Also: Esc cancels an in-progress queue edit (else interrupts).

Cleanups on the integrated code: fold the browse-state reset into the
existing session-change effect (drop the duplicate ref+effect); reuse
loadIntoComposer for history recall; sort imports; add curly braces +
the runDrain sessionId dep (lint).

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

@@ -24,6 +24,13 @@ 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 {
+  browseBackward,
+  browseForward,
+  deriveUserHistory,
+  isBrowsingHistory,
+  resetBrowseState
+} from '@/store/composer-input-history'
 import {
   $queuedPromptsBySession,
   enqueueQueuedPrompt,
@@ -33,13 +40,6 @@ import {
   shouldAutoDrainOnSettle,
   updateQueuedPrompt
 } from '@/store/composer-queue'
-import {
-  browseBackward,
-  browseForward,
-  deriveUserHistory,
-  isBrowsingHistory,
-  resetBrowseState
-} from '@/store/composer-input-history'
 import { $gatewayState, $messages } from '@/store/session'
 import { $threadScrolledUp } from '@/store/thread-scroll'
 
@@ -201,6 +201,7 @@ export function ChatBar({
       return
     }
 
+    resetBrowseState(prev)
     setRestingPlaceholder(pickPlaceholder(sessionId ? followUpPlaceholders : newSessionPlaceholders))
   }, [followUpPlaceholders, newSessionPlaceholders, sessionId])
 
@@ -255,16 +256,6 @@ export function ChatBar({
     }
   }, [disabled, focusInput, focusKey, focusRequestId])
 
-  // Reset input history browse state when the active session changes.
-  const prevSessionRef = useRef(sessionId)
-
-  useEffect(() => {
-    if (prevSessionRef.current !== sessionId) {
-      prevSessionRef.current = sessionId
-      resetBrowseState(sessionId)
-    }
-  }, [sessionId])
-
   useEffect(() => {
     if (disabled) {
       return undefined
@@ -733,14 +724,31 @@ export function ChatBar({
       }
     }
 
-    // ArrowUp/ArrowDown for input history navigation. The user-text ring is
-    // derived from the live session messages on every press — no mirror, no
-    // seeding, no dedup. Single source of truth: $messages.
+    // ArrowUp/ArrowDown navigate, in priority order: the queue (edit entries in
+    // place) then sent-message history. The history ring is derived from live
+    // session messages each press — single source of truth, no mirror.
     if (event.key === 'ArrowUp') {
       const currentDraft = draftRef.current
 
-      // Don't hijack Arrow Up when the user has an unsent draft and isn't
-      // already browsing — they'd lose what they typed.
+      // Editing a queued turn → walk to the older entry.
+      if (queueEdit && stepQueuedEdit(-1)) {
+        event.preventDefault()
+        triggerKeyConsumedRef.current = true
+
+        return
+      }
+
+      // Empty composer + a queued turn → open the newest queued entry for edit
+      // (the row's pencil), not a text recall. Enter saves it back to the queue.
+      if (!currentDraft.trim() && !queueEdit && queuedPrompts.length > 0) {
+        event.preventDefault()
+        triggerKeyConsumedRef.current = true
+        beginQueuedEdit(queuedPrompts[queuedPrompts.length - 1]!)
+
+        return
+      }
+
+      // Don't hijack a typed draft unless already browsing — they'd lose it.
       if (currentDraft.trim() && !isBrowsingHistory(sessionId)) {
         return
       }
@@ -752,21 +760,23 @@ export function ChatBar({
       const entry = browseBackward(sessionId, currentDraft, history)
 
       if (entry !== null) {
-        const editor = editorRef.current
-
-        draftRef.current = entry
-        aui.composer().setText(entry)
-
-        if (editor) {
-          renderComposerContents(editor, entry)
-          placeCaretEnd(editor)
-        }
+        loadIntoComposer(entry, $composerAttachments.get())
       }
 
       return
     }
 
     if (event.key === 'ArrowDown') {
+      // Editing a queued turn → walk to the newer entry (past the newest exits).
+      if (queueEdit) {
+        event.preventDefault()
+        triggerKeyConsumedRef.current = true
+        stepQueuedEdit(1)
+
+        return
+      }
+
+      // Browsing sent history → step toward the present, restoring the draft.
       if (isBrowsingHistory(sessionId)) {
         event.preventDefault()
         triggerKeyConsumedRef.current = true
@@ -775,21 +785,10 @@ export function ChatBar({
         const result = browseForward(sessionId, history)
 
         if (result !== null) {
-          const editor = editorRef.current
-
-          draftRef.current = result.text
-          aui.composer().setText(result.text)
-
-          if (editor) {
-            renderComposerContents(editor, result.text)
-            placeCaretEnd(editor)
-          }
+          loadIntoComposer(result.text, $composerAttachments.get())
         }
-
-        return
       }
 
-      // Not browsing — let the browser handle default cursor movement.
       return
     }
 
@@ -813,11 +812,21 @@ export function ChatBar({
       return
     }
 
-    // Esc interrupts the running turn (Stop-button parity).
-    if (event.key === 'Escape' && busy) {
-      event.preventDefault()
-      triggerHaptic('cancel')
-      void Promise.resolve(onCancel())
+    if (event.key === 'Escape') {
+      // Editing a queued turn → Esc cancels the edit, restoring the prior draft.
+      if (queueEdit) {
+        event.preventDefault()
+        exitQueuedEdit('cancel')
+
+        return
+      }
+
+      // Otherwise Esc interrupts the running turn (Stop-button parity).
+      if (busy) {
+        event.preventDefault()
+        triggerHaptic('cancel')
+        void Promise.resolve(onCancel())
+      }
     }
   }
 
@@ -983,6 +992,42 @@ export function ChatBar({
     focusInput()
   }
 
+  // Walk queued entries while editing (ArrowUp = older, ArrowDown = newer),
+  // saving the in-progress edit on each step. Stepping newer past the last
+  // entry exits edit mode and restores the pre-edit draft.
+  const stepQueuedEdit = (direction: -1 | 1) => {
+    if (!queueEdit) {
+      return false
+    }
+
+    const index = queuedPrompts.findIndex(e => e.id === queueEdit.entryId)
+    const target = index + direction
+
+    if (index < 0 || target < 0) {
+      return index >= 0 // at the oldest: swallow; missing entry: let it fall through
+    }
+
+    const saved = updateQueuedPrompt(queueEdit.sessionKey, queueEdit.entryId, {
+      attachments: cloneAttachments($composerAttachments.get()),
+      text: draftRef.current
+    })
+
+    const next = queuedPrompts[target]
+
+    if (next) {
+      setQueueEdit({ ...queueEdit, entryId: next.id })
+      loadIntoComposer(next.text, next.attachments)
+    } else {
+      setQueueEdit(null)
+      loadIntoComposer(queueEdit.draft, queueEdit.attachments)
+    }
+
+    triggerHaptic(saved ? 'success' : 'selection')
+    focusInput()
+
+    return true
+  }
+
   const exitQueuedEdit = (action: 'cancel' | 'save'): boolean => {
     if (!queueEdit) {
       return false
@@ -1058,7 +1103,7 @@ export function ChatBar({
         drainingQueueRef.current = false
       }
     },
-    [activeQueueSessionKey, onSubmit, queuedPrompts]
+    [activeQueueSessionKey, onSubmit, queuedPrompts, sessionId]
   )
 
   const drainNextQueued = useCallback(

apps/desktop/src/store/composer-input-history.ts

@@ -55,11 +55,11 @@ export function deriveUserHistory<T extends { role: string }>(
   for (let i = messages.length - 1; i >= 0; i--) {
     const m = messages[i]!
 
-    if (m.role !== 'user') continue
+    if (m.role !== 'user') {continue}
 
     const t = getText(m).trim()
 
-    if (t) out.push(t)
+    if (t) {out.push(t)}
   }
 
   return out
@@ -138,7 +138,7 @@ export function resetBrowseState(sessionId: string | null | undefined) {
   const all = { ...$perSessionBrowse.get() }
   const existing = all[sessionId]
 
-  if (!existing) return
+  if (!existing) {return}
 
   all[sessionId] = { cursor: -1, draftSnapshot: '' }
   $perSessionBrowse.set(all)