chore: add sproutclaw git workflow and track local extensions

Document main/upstream-sync/feature branch strategy, add sync/push
scripts, track .pi/agent extensions and webui in git, and disable
startup changelog via showChangelogOnStartup.

Co-authored-by: Cursor <cursoragent@cursor.com>

.pi/agent/extensions/sproutclaw-setup.ts

@@ -0,0 +1,63 @@
+/**
+ * sproutclaw / mengya 命令安装扩展
+ *
+ * 启动后自动在 /usr/local/bin/ 下创建 mengya 和 sproutclaw 命令，
+ * 方便快速启动 sproutclaw（cd 到项目目录并执行 ./pi-test.sh）。
+ *
+ * 命令 /install-commands 可随时手动重装。
+ */
+
+import { existsSync, writeFileSync, chmodSync, readFileSync } from "node:fs";
+import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
+
+const SPROUTCLAW_DIR = "/shumengya/project/agent/sproutclaw";
+const BIN_DIR = "/usr/local/bin";
+const COMMANDS = ["mengya", "sproutclaw"];
+
+/** 创建或修复命令脚本 */
+function installCommand(name: string): boolean {
+	const path = `${BIN_DIR}/${name}`;
+
+	const script = `#!/usr/bin/env bash
+set -euo pipefail
+cd ${SPROUTCLAW_DIR}
+exec ./pi-test.sh "$@"
+`;
+	if (existsSync(path)) {
+		try {
+			const current = readFileSync(path, "utf-8");
+			if (current === script) return false;
+		} catch {
+			// Rewrite unreadable or invalid command files below.
+		}
+	}
+	writeFileSync(path, script, "utf-8");
+	chmodSync(path, 0o755);
+	return true;
+}
+
+export default function (pi: ExtensionAPI) {
+	// 启动时自动安装
+	for (const name of COMMANDS) {
+		const created = installCommand(name);
+		if (created) {
+			console.log(`[sproutclaw-setup] Created /usr/local/bin/${name}`);
+		}
+	}
+
+	// 命令：手动重装
+	pi.registerCommand("install-commands", {
+		description: "Install mengya and sproutclaw commands to /usr/local/bin",
+		handler: async (_args, ctx) => {
+			let count = 0;
+			for (const name of COMMANDS) {
+				if (installCommand(name)) count++;
+			}
+			if (count > 0) {
+				ctx.ui.notify(`Installed ${count} command(s): mengya, sproutclaw`, "success");
+			} else {
+				ctx.ui.notify("Both commands already exist", "info");
+			}
+		},
+	});
+}