Add toast notification system and improve error handling

- Created useToast composable with success/error/warning/info methods
- Added ToastContainer component with animations and colors
- Integrated toast notifications throughout the app:
  * Upload success/failure feedback
  * OCR completion/failure notifications
  * Replaced alert() with toast messages
- Fixed HTML validation warning (div inside p tag)
- Added automatic toast notifications on job status changes

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

client/src/App.vue

@@ -1,9 +1,11 @@
 <template>
   <div id="app" class="min-h-screen">
     <RouterView />
+    <ToastContainer />
   </div>
 </template>
 
 <script setup>
 import { RouterView } from 'vue-router'
+import ToastContainer from './components/ToastContainer.vue'
 </script>

client/src/components/ToastContainer.vue

@@ -0,0 +1,86 @@
+<template>
+  <div class="fixed top-4 right-4 z-50 space-y-2 max-w-md">
+    <TransitionGroup name="toast">
+      <div
+        v-for="toast in toasts"
+        :key="toast.id"
+        :class="[
+          'flex items-start gap-3 p-4 rounded-xl shadow-2xl backdrop-blur-lg border',
+          'animate-slide-in-right',
+          toastClasses[toast.type]
+        ]"
+      >
+        <div class="flex-shrink-0">
+          <svg v-if="toast.type === 'success'" class="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 12l2 2 4-4m6 2a9 9 0 11-18 0 9 9 0 0118 0z" />
+          </svg>
+          <svg v-else-if="toast.type === 'error'" class="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M12 8v4m0 4h.01M21 12a9 9 0 11-18 0 9 9 0 0118 0z" />
+          </svg>
+          <svg v-else-if="toast.type === 'warning'" class="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M12 9v2m0 4h.01m-6.938 4h13.856c1.54 0 2.502-1.667 1.732-3L13.732 4c-.77-1.333-2.694-1.333-3.464 0L3.34 16c-.77 1.333.192 3 1.732 3z" />
+          </svg>
+          <svg v-else class="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M13 16h-1v-4h-1m1-4h.01M21 12a9 9 0 11-18 0 9 9 0 0118 0z" />
+          </svg>
+        </div>
+        <div class="flex-1 min-w-0">
+          <p class="text-sm font-medium leading-relaxed">{{ toast.message }}</p>
+        </div>
+        <button
+          @click="removeToast(toast.id)"
+          class="flex-shrink-0 opacity-70 hover:opacity-100 transition-opacity"
+        >
+          <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M6 18L18 6M6 6l12 12" />
+          </svg>
+        </button>
+      </div>
+    </TransitionGroup>
+  </div>
+</template>
+
+<script setup>
+import { useToast } from '../composables/useToast'
+
+const { toasts, removeToast } = useToast()
+
+const toastClasses = {
+  success: 'bg-green-500/20 border-green-400/30 text-green-100',
+  error: 'bg-red-500/20 border-red-400/30 text-red-100',
+  warning: 'bg-yellow-500/20 border-yellow-400/30 text-yellow-100',
+  info: 'bg-blue-500/20 border-blue-400/30 text-blue-100',
+}
+</script>
+
+<style scoped>
+.toast-enter-active,
+.toast-leave-active {
+  transition: all 0.3s ease;
+}
+
+.toast-enter-from {
+  opacity: 0;
+  transform: translateX(100px);
+}
+
+.toast-leave-to {
+  opacity: 0;
+  transform: translateX(100px);
+}
+
+@keyframes slide-in-right {
+  from {
+    opacity: 0;
+    transform: translateX(100px);
+  }
+  to {
+    opacity: 1;
+    transform: translateX(0);
+  }
+}
+
+.animate-slide-in-right {
+  animation: slide-in-right 0.3s ease-out;
+}
+</style>

client/src/components/UploadModal.vue

@@ -57,10 +57,10 @@
                   <div class="flex-1">
                     <p class="font-medium text-white">{{ selectedFile.name }}</p>
                     <p class="text-sm text-white/70">{{ formatFileSize(selectedFile.size) }}</p>
-                    <p v-if="extractingMetadata" class="text-xs text-pink-400 mt-1 flex items-center gap-1">
+                    <div v-if="extractingMetadata" class="text-xs text-pink-400 mt-1 flex items-center gap-1">
                       <div class="spinner border-pink-400" style="width: 12px; height: 12px; border-width: 2px;"></div>
                       Extracting metadata from first page...
-                    </p>
+                    </div>
                   </div>
                 </div>
                 <button
@@ -227,6 +227,7 @@
 import { ref, computed } from 'vue'
 import { useRouter } from 'vue-router'
 import { useJobPolling } from '../composables/useJobPolling'
+import { useToast } from '../composables/useToast'
 
 const props = defineProps({
   isOpen: {
@@ -238,6 +239,7 @@ const props = defineProps({
 const emit = defineEmits(['close', 'upload-success'])
 
 const router = useRouter()
+const toast = useToast()
 const fileInput = ref(null)
 const selectedFile = ref(null)
 const isDragging = ref(false)
@@ -416,7 +418,7 @@ async function uploadFile() {
   } catch (error) {
     console.error('Upload error:', error)
     errorMessage.value = error.message
-    alert(`Upload failed: ${error.message}`)
+    toast.error(`Upload failed: ${error.message}`)
   } finally {
     uploading.value = false
   }

client/src/composables/useJobPolling.js

@@ -4,8 +4,10 @@
  */
 
 import { ref, onUnmounted } from 'vue'
+import { useToast } from './useToast'
 
 export function useJobPolling() {
+  const toast = useToast()
   const jobId = ref(null)
   const jobStatus = ref('pending')
   const jobProgress = ref(0)
@@ -45,9 +47,20 @@ export function useJobPolling() {
       const data = await response.json()
 
       if (response.ok) {
+        const previousStatus = jobStatus.value
         jobStatus.value = data.status
         jobProgress.value = data.progress || 0
         jobError.value = data.error || null
+
+        // Show success toast when job completes
+        if (previousStatus !== 'completed' && data.status === 'completed') {
+          toast.success('Document processed successfully! OCR complete.')
+        }
+
+        // Show error toast when job fails
+        if (previousStatus !== 'failed' && data.status === 'failed') {
+          toast.error(`Processing failed: ${data.error || 'Unknown error'}`)
+        }
       } else {
         console.error('Poll error:', data.error)
         // Don't stop polling on transient errors

client/src/composables/useToast.js

@@ -0,0 +1,64 @@
+import { ref } from 'vue'
+
+const toasts = ref([])
+let toastId = 0
+
+export function useToast() {
+  function showToast(message, type = 'info', duration = 5000) {
+    const id = toastId++
+    const toast = {
+      id,
+      message,
+      type, // 'success', 'error', 'warning', 'info'
+      duration,
+    }
+
+    toasts.value.push(toast)
+
+    if (duration > 0) {
+      setTimeout(() => {
+        removeToast(id)
+      }, duration)
+    }
+
+    return id
+  }
+
+  function removeToast(id) {
+    const index = toasts.value.findIndex(t => t.id === id)
+    if (index > -1) {
+      toasts.value.splice(index, 1)
+    }
+  }
+
+  function success(message, duration = 4000) {
+    return showToast(message, 'success', duration)
+  }
+
+  function error(message, duration = 6000) {
+    return showToast(message, 'error', duration)
+  }
+
+  function warning(message, duration = 5000) {
+    return showToast(message, 'warning', duration)
+  }
+
+  function info(message, duration = 4000) {
+    return showToast(message, 'info', duration)
+  }
+
+  function clear() {
+    toasts.value = []
+  }
+
+  return {
+    toasts,
+    showToast,
+    removeToast,
+    success,
+    error,
+    warning,
+    info,
+    clear,
+  }
+}