chore: bump version to 0.3.0

feat(shell): real terminal with xterm.js + PTY over WebSocket

Replace fake shell input with a full PTY-backed terminal using xterm.js.
Apps like btop, vim, htop now work. AI chat panel is always visible.

Backend:
- Add WebSocket handler /api/ws/terminal with creack/pty
- Allocate real pseudo-terminal with TERM=xterm-256color
- Bidirectional I/O + dynamic resize via pty.Setsize
- Skip JSON headers on /api/ws/* paths for WebSocket upgrade

Frontend:
- Integrate xterm.js with FitAddon and WebLinksAddon
- Cyberpunk color theme matching app design
- ResizeObserver for automatic terminal resizing
- AI assistant panel always visible (340px, no toggle)
- Connection status indicator (green/red dot)

Dependencies:
- Go: github.com/gorilla/websocket, github.com/creack/pty/v2
- npm: @xterm/xterm, @xterm/addon-fit, @xterm/addon-web-links

💘 Generated with Crush

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

internal/orchestrator/orchestrator.go

@@ -41,11 +41,12 @@ type ChatResponse struct {
 }
 
 type Orchestrator struct {
-	config   *config.MuyueConfig
-	provider *config.AIProvider
-	client   *http.Client
-	history  []Message
-	histMu   sync.Mutex
+	config       *config.MuyueConfig
+	provider     *config.AIProvider
+	client       *http.Client
+	history      []Message
+	histMu       sync.Mutex
+	systemPrompt string
 }
 
 var sharedHTTPClient = &http.Client{
@@ -77,6 +78,10 @@ func New(cfg *config.MuyueConfig) (*Orchestrator, error) {
 	}, nil
 }
 
+func (o *Orchestrator) SetSystemPrompt(prompt string) {
+	o.systemPrompt = prompt
+}
+
 func (o *Orchestrator) Send(userMessage string) (string, error) {
 	o.histMu.Lock()
 	o.history = append(o.history, Message{
@@ -88,9 +93,15 @@ func (o *Orchestrator) Send(userMessage string) (string, error) {
 		o.history = o.history[len(o.history)-maxHistorySize:]
 	}
 
+	messages := make([]Message, 0, len(o.history)+1)
+	if o.systemPrompt != "" {
+		messages = append(messages, Message{Role: "system", Content: o.systemPrompt})
+	}
+	messages = append(messages, o.history...)
+
 	reqBody := ChatRequest{
 		Model:    o.provider.Model,
-		Messages: o.history,
+		Messages: messages,
 		Stream:   false,
 	}
 	o.histMu.Unlock()