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/webui/frontend/scripts/generate-icons.mjs

@@ -0,0 +1,22 @@
+import { existsSync } from "node:fs";
+import { dirname, join } from "node:path";
+import { fileURLToPath } from "node:url";
+import sharp from "sharp";
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const publicDir = join(__dirname, "..", "public");
+const source = join(publicDir, "logo.png");
+
+if (!existsSync(source)) {
+	console.warn("[generate-icons] logo.png not found, skipping");
+	process.exit(0);
+}
+
+for (const size of [192, 512]) {
+	const out = join(publicDir, `logo${size}.png`);
+	await sharp(source)
+		.resize(size, size, { fit: "contain", background: { r: 0, g: 0, b: 0, alpha: 0 } })
+		.png()
+		.toFile(out);
+	console.log(`[generate-icons] wrote ${out}`);
+}