feat: conditional webhook/polling for openclaw compatibility

- Webhook server + notification poller only start when needed:
  - pi-bot (no GITEA_HOOKS_URL): starts automatically (persistent session)
  - openclaw (GITEA_HOOKS_URL set): tools only, no server/poller
  - Override with GITEA_ENABLE_POLLING=1 to force polling in any mode
- Tools (20 Gitea tools) always register regardless of mode

pi-extension/index.ts

@@ -75,6 +75,12 @@ export default function (pi: ExtensionAPI) {
 
 	// ── Lifecycle ────────────────────────────────────────────────────────────
 
+	// GITEA_ENABLE_POLLING=1 opts in to running the webhook server + notification poller.
+	// pi-bot (persistent session): enabled by default
+	// openclaw (ephemeral sessions): disabled by default — events come via openclaw hooks
+	const enablePolling = process.env.GITEA_ENABLE_POLLING === "1" ||
+		(!process.env.GITEA_HOOKS_URL && !process.env.OPENCLAW_HOOKS_URL);
+
 	pi.on("session_start", async (_event, ctx) => {
 		console.log("[pi-gitea] Session started");
 
@@ -108,17 +114,23 @@ export default function (pi: ExtensionAPI) {
 			});
 		}
 
+		if (enablePolling) {
 			try {
 				await startWebhookServer(pi);
 				await startPolling(pi);
 			} catch (err) {
-			console.error("[pi-gitea] Failed to start:", err);
+				console.error("[pi-gitea] Failed to start webhook/polling:", err);
+			}
+		} else {
+			console.log("[pi-gitea] Webhook server + polling disabled (openclaw mode — tools only)");
 		}
 	});
 
 	pi.on("session_shutdown", async () => {
 		console.log("[pi-gitea] Session shutting down");
+		if (enablePolling) {
 			await stopWebhookServer();
 			stopPolling();
+		}
 	});
 }