feat(coding-agent): mark experimental sessions in footer

packages/coding-agent/src/modes/interactive/components/footer.ts

@@ -1,6 +1,7 @@
 import { isAbsolute, relative, resolve, sep } from "node:path";
 import { type Component, truncateToWidth, visibleWidth } from "@earendil-works/pi-tui";
 import type { AgentSession } from "../../../core/agent-session.ts";
+import { areExperimentalFeaturesEnabled } from "../../../core/experimental.ts";
 import type { ReadonlyFooterDataProvider } from "../../../core/footer-data-provider.ts";
 import { theme } from "../theme/theme.ts";
 
@@ -159,6 +160,9 @@ export class FooterComponent implements Component {
 			contextPercentStr = contextPercentDisplay;
 		}
 		statsParts.push(contextPercentStr);
+		if (areExperimentalFeaturesEnabled()) {
+			statsParts.push(`${theme.fg("dim", "•")} ${theme.bold(theme.fg("warning", "xp"))}`);
+		}
 
 		let statsLeft = statsParts.join(" ");