feat: auto-detect pi-bot vs openclaw runtime for event delivery

- pi-bot: uses ctx.sendUserMessage (persistent session, followUp mode)
- openclaw: POSTs to /hooks/agent endpoint (request/response model)
- Detection: checks if ctx.sendUserMessage exists on session_start
- openclaw env vars: OPENCLAW_HOOKS_URL, OPENCLAW_HOOKS_PATH, OPENCLAW_HOOKS_TOKEN
- Same extension, tools, poller, and @mention routing work in both runtimes

pi-extension/index.ts

@@ -78,11 +78,35 @@ export default function (pi: ExtensionAPI) {
 	pi.on("session_start", async (_event, ctx) => {
 		console.log("[pi-gitea] Session started");
 
-		const sendMessageFn = (msg: string) => {
+		// Auto-detect runtime: pi-bot (persistent session) vs openclaw (hooks endpoint)
+		if (ctx.sendUserMessage) {
+			// pi-bot: inject directly into the running session
+			console.log("[pi-gitea] Delivery: sendUserMessage (pi-bot mode)");
+			setSendMessage((msg: string) => {
 				ctx.sendUserMessage(msg, { deliverAs: "followUp" });
 				return Promise.resolve();
-		};
-		setSendMessage(sendMessageFn);
+			});
+		} else {
+			// openclaw: POST to the hooks endpoint
+			const hooksUrl = process.env.OPENCLAW_HOOKS_URL ?? "http://localhost:3001";
+			const hooksPath = process.env.OPENCLAW_HOOKS_PATH ?? "/hooks/agent";
+			const hooksToken = process.env.OPENCLAW_HOOKS_TOKEN ?? "";
+			console.log(`[pi-gitea] Delivery: openclaw hooks (${hooksUrl}${hooksPath})`);
+			setSendMessage(async (msg: string) => {
+				const res = await fetch(`${hooksUrl}${hooksPath}`, {
+					method: "POST",
+					headers: {
+						"Content-Type": "application/json",
+						...(hooksToken ? { Authorization: `Bearer ${hooksToken}` } : {}),
+					},
+					body: JSON.stringify({ message: msg }),
+				});
+				if (!res.ok) {
+					const body = await res.text().catch(() => "");
+					throw new Error(`Hooks POST failed: ${res.status} ${body}`);
+				}
+			});
+		}
 
 		try {
 			await startWebhookServer(pi);