feat: RAG, memory, plugins, lessons, file editor, split panes, Markdown rendering, PWA + UI overhaul

Major additions:
- RAG pipeline (indexing, chunking, search) with sidebar upload button
- Memory system with CRUD API
- Plugins and lessons modules
- MCP discovery and MCP server
- Advanced skills (auto-create, conditional, improver)
- Agent browser/image support, delegate, sessions
- File editor with CodeMirror in split panes
- Markdown rendering via react-markdown + KaTeX + highlight.js
- Raw markdown toggle
- PWA manifest + service worker
- Extension UI redesign with new design tokens and studio-style chat
- Pipeline API for chat streaming
- Mobile responsive layout

💘 Generated with Crush

Assisted-by: GLM-5.1 via Crush <crush@charm.land>

web/vite.config.js

@@ -3,9 +3,13 @@ import react from '@vitejs/plugin-react'
 
 export default defineConfig({
   plugins: [react()],
+  css: {
+    transformer: 'postcss',
+  },
   build: {
     outDir: 'dist',
     emptyOutDir: true,
+    cssMinify: false,
   },
   server: {
     port: 5173,