feat: 5-issue fix — OCR image parse bug + Vue frontend feature parity + streaming UX

Fix 1 (CRITICAL): file_parser.py suffix normalization ".jpg", api_server.py Path.suffix
Fix 2: Sidebar version history download, ProcessSection replaces old components
Fix 3: OCR content/position layer structured logging in agent/nodes.py
Fix 4: collapsible process sections with per-section stream routing + auto-fold
Fix 5: agent_complete total_duration_ms, SummaryCard duration display

- backend/file_parser.py: normalize suffix to always include leading dot
- api_server.py: step_index in node_start, total_duration_ms in agent_complete
- agent/nodes.py: _log_ocr_layers() for [内容层]/[位置层]/[合并] logging
- frontend: ProcessSection.vue (NEW), chat.ts sections model, Sidebar versions
- CLAUDE.md: updated component list and v6 changelog

frontend/src/App.vue

@@ -5,8 +5,7 @@ import { useSessionStore } from './stores/session'
 import { api } from './api/client'
 import Sidebar from './components/Sidebar.vue'
 import ChatMessages from './components/ChatMessages.vue'
-import StreamingMessage from './components/StreamingMessage.vue'
-import NodeProgress from './components/NodeProgress.vue'
+import ProcessSection from './components/ProcessSection.vue'
 import SummaryCard from './components/SummaryCard.vue'
 import UnifiedInput from './components/UnifiedInput.vue'
 
@@ -55,7 +54,7 @@ async function handleSend(text: string, files: File[]) {
   try {
     await api.chat(session.currentId, text, remoteIds, {
       onNodeStart(data) {
-        chat.addNode(data)
+        chat.addNode({ node: data.node, label: data.label, step_index: data.step_index })
       },
       onNodeComplete(data) {
         chat.completeNode(data)
@@ -72,6 +71,7 @@ async function handleSend(text: string, files: File[]) {
           error_msg: data.error_msg,
           natural_explanation: data.natural_explanation,
           retry_count: data.retry_count,
+          total_duration_ms: data.total_duration_ms,
           ocr_extraction_result: data.ocr_extraction_result,
         })
 
@@ -119,8 +119,7 @@ async function handleSend(text: string, files: File[]) {
     <main class="main-area">
       <div class="chat-container" ref="chatContainer">
         <ChatMessages />
-        <StreamingMessage />
-        <NodeProgress />
+        <ProcessSection />
         <SummaryCard />
       </div>