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>

internal/config/config.go

@@ -51,6 +51,16 @@ type SSHConnection struct {
 	KeyPath  string `yaml:"key_path,omitempty" json:"key_path,omitempty"`
 }
 
+type PluginsConfig struct {
+	Enabled []string `yaml:"enabled" json:"enabled"`
+	Paths   []string `yaml:"paths,omitempty" json:"paths,omitempty"`
+}
+
+type LessonsConfig struct {
+	Dirs    []string `yaml:"dirs,omitempty" json:"dirs,omitempty"`
+	Enabled bool     `yaml:"enabled" json:"enabled"`
+}
+
 type MuyueConfig struct {
 	Version   string               `yaml:"version"   json:"version"`
 	Profile   Profile              `yaml:"profile"   json:"profile"`
@@ -71,6 +81,8 @@ type MuyueConfig struct {
 		FontFamily   string          `yaml:"font_family"   json:"font_family"`
 		Theme        string          `yaml:"theme"         json:"theme"`
 	} `yaml:"terminal" json:"terminal"`
+	Plugins PluginsConfig `yaml:"plugins" json:"plugins"`
+	Lessons LessonsConfig `yaml:"lessons" json:"lessons"`
 }
 
 type TerminalTheme struct {
@@ -322,5 +334,11 @@ func Default() *MuyueConfig {
 	cfg.Terminal.PromptTheme = "zerotwo"
 	cfg.Terminal.FontSize = 14
 
+	cfg.Plugins.Enabled = []string{}
+	cfg.Plugins.Paths = []string{}
+
+	cfg.Lessons.Enabled = true
+	cfg.Lessons.Dirs = []string{}
+
 	return cfg
 }