fix(coding-agent): add entry renderers for session entries

packages/coding-agent/examples/extensions/README.md

@@ -112,6 +112,7 @@ cp permission-gate.ts ~/.pi/agent/extensions/
 | Extension | Description |
 |-----------|-------------|
 | `message-renderer.ts` | Custom message rendering with colors and expandable details via `registerMessageRenderer` |
+| `entry-renderer.ts` | TUI-only session entry rendering via `appendEntry` and `registerEntryRenderer` |
 | `event-bus.ts` | Inter-extension communication via `pi.events` |
 
 ### Session Metadata

packages/coding-agent/examples/extensions/entry-renderer.ts

@@ -0,0 +1,41 @@
+/**
+ * Custom entry rendering example.
+ *
+ * Shows how to render durable extension data inside the chat without sending it
+ * to the LLM. Custom entries are stored in the session via pi.appendEntry() and
+ * rendered in interactive mode via pi.registerEntryRenderer().
+ *
+ * Usage: /status-card [message]
+ */
+
+import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
+import { Box, Text } from "@earendil-works/pi-tui";
+
+interface StatusCardData {
+	message: string;
+	timestamp: number;
+}
+
+export default function (pi: ExtensionAPI) {
+	pi.registerEntryRenderer<StatusCardData>("status-card", (entry, { expanded }, theme) => {
+		const data = entry.data ?? { message: "No data", timestamp: Date.now() };
+		const box = new Box(1, 1, (text) => theme.bg("customMessageBg", text));
+		box.addChild(new Text(`${theme.fg("accent", "[status]")} ${data.message}`, 0, 0));
+
+		if (expanded) {
+			box.addChild(new Text(theme.fg("dim", new Date(data.timestamp).toLocaleString()), 0, 0));
+		}
+
+		return box;
+	});
+
+	pi.registerCommand("status-card", {
+		description: "Render a durable status card that is not sent to the LLM",
+		handler: async (args) => {
+			pi.appendEntry<StatusCardData>("status-card", {
+				message: args.trim() || "Status card",
+				timestamp: Date.now(),
+			});
+		},
+	});
+}