feat: 增强聊天 UI 与终端配置

- 重构消息列表、思考块与工具调用块样式
- ChatContext 支持 agent 分段与 markdown 渲染优化
- 后端增加 PI 命令配置与 Web 终端改进
- 新增 run-backend.sh 启动脚本，忽略 backend/dist 构建产物

backend/internal/handlers/settings.go

@@ -225,25 +225,26 @@ func handleEnvironment(cfg *config.Config) gin.HandlerFunc {
 		}
 
 		c.JSON(http.StatusOK, gin.H{
-			"goVersion":   runtime.Version(),
-			"platform":    runtime.GOOS,
-			"arch":        runtime.GOARCH,
-			"osRelease":   osRelease,
-			"hostname":    hostname,
-			"numCPU":      runtime.NumCPU(),
-			"totalMemMb":  totalMemMb,
-			"freeMemMb":   freeMemMb,
-			"pid":         os.Getpid(),
-			"uptime":      uptimeSec,
-			"execPath":    exe,
-			"goroutines":  runtime.NumGoroutine(),
-			"goHeapMb":    goHeapMb,
-			"cwd":         cwd,
-			"port":        cfg.Port,
-			"agentDir":    cfg.AgentDir,
-			"dataDir":     cfg.DataDir,
-			"repoRoot":    cfg.RepoRoot,
-			"piCmd": piCmd,
+			"goVersion":     runtime.Version(),
+			"platform":      runtime.GOOS,
+			"arch":          runtime.GOARCH,
+			"osRelease":     osRelease,
+			"hostname":      hostname,
+			"numCPU":        runtime.NumCPU(),
+			"totalMemMb":    totalMemMb,
+			"freeMemMb":     freeMemMb,
+			"pid":           os.Getpid(),
+			"uptime":        uptimeSec,
+			"execPath":      exe,
+			"goroutines":    runtime.NumGoroutine(),
+			"goHeapMb":      goHeapMb,
+			"cwd":           cwd,
+			"port":          cfg.Port,
+			"agentDir":      cfg.AgentDir,
+			"dataDir":       cfg.DataDir,
+			"repoRoot":      cfg.RepoRoot,
+			"piCmd":         piCmd,
+			"sproutclawCmd": piCmd,
 			"memUsagePct": func() string {
 				if totalMemMb == 0 {
 					return ""

backend/internal/handlers/terminal.go

@@ -37,7 +37,7 @@ func handleTerminalWS(cfg *config.Config) gin.HandlerFunc {
 		}
 		defer conn.Close()
 
-		if err := services.ServeWebTerminal(conn, cfg.RepoRoot); err != nil {
+		if err := services.ServeWebTerminal(conn, cfg.RepoRoot, cfg.AgentDir); err != nil {
 			_ = conn.WriteJSON(gin.H{"type": "error", "error": err.Error()})
 		}
 	}