fix: restore buffer after WebSocket init, fix clear detection, fix streaming chunks

- Delay buffer restoration by 300ms to avoid race condition with WebSocket init
- Read current line from terminal buffer on Enter (reliable) instead of keystroke tracking
- Fix streaming to emit full content instead of word-by-word chunks
- Fix WebSocket readyState check in sendToTerminal
- Extract and deduplicate AI message sending logic
- Fix localStorage cleanup on tab close

💘 Generated with Crush

Assisted-by: MiniMax-M2.7 via Crush <crush@charm.land>

internal/api/chat_engine.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"encoding/json"
 	"net/http"
-	"strings"
 
 	"github.com/muyue/muyue/internal/agent"
 	"github.com/muyue/muyue/internal/orchestrator"
@@ -76,12 +75,8 @@ func (ce *ChatEngine) RunWithTools(ctx context.Context, messages []orchestrator.
 		content := cleanThinkingTags(choice.Message.Content)
 
 		if content != "" {
-			words := strings.Fields(content)
-			for _, w := range words {
-				chunk := w
-				if ce.onChunk != nil {
-					ce.onChunk(map[string]interface{}{"content": chunk})
-				}
+			if ce.onChunk != nil {
+				ce.onChunk(map[string]interface{}{"content": content})
 			}
 			finalContent = content
 		}