feat(web): add markdown syntax highlighting, slash commands, stop button, quote/reply

- PromptEditor with Prism.js syntax highlighting
- Slash commands (/run, /status, /images, /list, /help) in chat input
- Stop button to cancel ongoing generation
- Quote/reply and regenerate/continue actions in chat
- MiddlePanel with conversation timestamps and preview
- Pipeline progress in chat view
- Fix all remaining dark theme classes

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.claude/skills/config.json

@@ -1,6 +1,6 @@
 {
-"jianyingDraftPath": "/Users/lc/Movies/JianyingPro/User Data/Projects/com.lveditor.draft",
-  "capcutMateDir": "/Users/lc/capcut-mate",
+  "jianyingDraftPath": "C:/Users/45070/AppData/Local/JianyingPro/User Data/Projects/com.lveditor.draft",
+  "capcutMateDir": "C:/Users/45070/capcut-mate",
   "capcutMateApiBase": "http://capcut.muyetools.cn/openapi/capcut-mate/v1",
   "imgbbApiKey": "deprecated",
   "geminiApiBaseUrl": "https://yunwu.ai",