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/redraws.ts

@@ -0,0 +1,24 @@
+/**
+ * Redraws Extension
+ *
+ * Exposes /tui to show TUI redraw stats.
+ */
+
+import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
+import { Text } from "@earendil-works/pi-tui";
+
+export default function (pi: ExtensionAPI) {
+	pi.registerCommand("tui", {
+		description: "Show TUI stats",
+		handler: async (_args, ctx) => {
+			if (!ctx.hasUI) return;
+			let redraws = 0;
+			await ctx.ui.custom<void>((tui, _theme, _keybindings, done) => {
+				redraws = tui.fullRedraws;
+				done(undefined);
+				return new Text("", 0, 0);
+			});
+			ctx.ui.notify(`TUI full redraws: ${redraws}`, "info");
+		},
+	});
+}