fix: stale chunk auto-reload + image paste upload UX

- Add lazyWithRetry wrapper for all lazy-loaded routes to auto-reload
  on stale chunk errors after deploys (prevents ErrorBoundary flash)
- Show toast notification when image paste/upload fails due to storage
  not configured (503), instead of silent tiny error thumbnails
- Remove failed uploads from thumbnail strip on 503 (was showing
  confusing retry icon)
- Pass completed upload IDs in navigation state from dashboard input
- Suppress Sentry dialog for chunk load errors (deploy artifacts)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/common/ErrorBoundary.tsx

@@ -70,7 +70,14 @@ export function ErrorBoundary({ children, fallback }: Props) {
         if (fallback) return fallback as React.ReactElement
         return <DefaultFallback error={error as Error} resetError={resetError} />
       }}
-      showDialog
+      beforeCapture={(scope, error) => {
+        // Don't report chunk load errors to Sentry — they're deploy artifacts, not bugs
+        if (error && isChunkLoadError(error as Error)) {
+          scope.setLevel('info')
+          scope.setTag('chunk_load_error', 'true')
+        }
+      }}
+      showDialog={false}
     >
       {children}
     </Sentry.ErrorBoundary>

frontend/src/components/dashboard/StartSessionInput.tsx

@@ -3,6 +3,7 @@ import { useNavigate } from 'react-router-dom'
 import { Send, Paperclip, Terminal, Loader2, X, RotateCcw, ImagePlus } from 'lucide-react'
 import { cn } from '@/lib/utils'
 import { uploadsApi } from '@/api/uploads'
+import { toast } from '@/lib/toast'
 import type { PendingUpload } from '@/types/upload'
 
 const SUGGESTIONS = [
@@ -44,6 +45,12 @@ export function StartSessionInput() {
     if (logContent.trim()) {
       state.logs = logContent.trim()
     }
+    const completedUploadIds = pendingUploads
+      .filter((u) => u.status === 'done' && u.result?.id)
+      .map((u) => u.result!.id)
+    if (completedUploadIds.length > 0) {
+      state.uploadIds = completedUploadIds
+    }
     navigate('/assistant', { state })
   }
 
@@ -81,12 +88,16 @@ export function StartSessionInput() {
           )
         })
         .catch((err) => {
-          const errorMsg = err?.response?.status === 503
+          const is503 = err?.response?.status === 503
+          const errorMsg = is503
             ? 'File uploads not available'
             : err?.message || 'Upload failed'
-          setPendingUploads((prev) =>
-            prev.map((u) => u.id === upload.id ? { ...u, status: 'error' as const, error: errorMsg } : u)
-          )
+          if (is503) {
+            toast.warning('Image attachments are not available yet — describe the issue in text instead')
+          } else {
+            toast.error(`Upload failed: ${errorMsg}`)
+          }
+          setPendingUploads((prev) => prev.filter((u) => u.id !== upload.id))
         })
     })
   }, [])

frontend/src/components/flowpilot/FlowPilotMessageBar.tsx

@@ -2,6 +2,7 @@ import { useState, useRef, useCallback, useEffect } from 'react'
 import { Send, Paperclip, Terminal, Loader2, X, RotateCcw, ImagePlus } from 'lucide-react'
 import { cn } from '@/lib/utils'
 import { uploadsApi } from '@/api/uploads'
+import { toast } from '@/lib/toast'
 import type { StepResponseRequest } from '@/types/ai-session'
 import type { PendingUpload } from '@/types/upload'
 
@@ -81,12 +82,13 @@ export function FlowPilotMessageBar({ onRespond, disabled = false, isProcessing
           )
         })
         .catch((err) => {
-          const errorMsg = err?.response?.status === 503
-            ? 'File uploads not available'
-            : err?.message || 'Upload failed'
-          setPendingUploads((prev) =>
-            prev.map((u) => u.id === upload.id ? { ...u, status: 'error' as const, error: errorMsg } : u)
-          )
+          const is503 = err?.response?.status === 503
+          if (is503) {
+            toast.warning('Image attachments are not available yet — describe the issue in text instead')
+          } else {
+            toast.error(`Upload failed: ${err?.message || 'Unknown error'}`)
+          }
+          setPendingUploads((prev) => prev.filter((u) => u.id !== upload.id))
         })
     })
   }, [])

frontend/src/components/tree-editor/TreeEditorLayout.tsx

@@ -1,4 +1,5 @@
-import { lazy, Suspense } from 'react'
+import { Suspense } from 'react'
+import { lazyWithRetry } from '@/lib/lazyWithRetry'
 import { TreePreviewPanel } from '@/components/tree-preview/TreePreviewPanel'
 import { FlowCanvas } from './FlowCanvas'
 import { NodeEditorPanel } from './NodeEditorPanel'
@@ -8,7 +9,7 @@ import { cn } from '@/lib/utils'
 import { Spinner } from '@/components/common/Spinner'
 
 // Lazy load CodeModeEditor (Monaco is ~2MB)
-const CodeModeEditor = lazy(() =>
+const CodeModeEditor = lazyWithRetry(() =>
   import('./code-mode/CodeModeEditor').then(m => ({ default: m.CodeModeEditor }))
 )