feat: integrate Pi backend and Pi Web

pi/packages/coding-agent/examples/extensions/file-trigger.ts

@@ -0,0 +1,41 @@
+/**
+ * File Trigger Extension
+ *
+ * Watches a trigger file and injects its contents into the conversation.
+ * Useful for external systems to send messages to the agent.
+ *
+ * Usage:
+ *   echo "Run the tests" > /tmp/agent-trigger.txt
+ */
+
+import * as fs from "node:fs";
+import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
+
+export default function (pi: ExtensionAPI) {
+	pi.on("session_start", async (_event, ctx) => {
+		const triggerFile = "/tmp/agent-trigger.txt";
+
+		fs.watch(triggerFile, () => {
+			try {
+				const content = fs.readFileSync(triggerFile, "utf-8").trim();
+				if (content) {
+					pi.sendMessage(
+						{
+							customType: "file-trigger",
+							content: `External trigger: ${content}`,
+							display: true,
+						},
+						{ triggerTurn: true }, // triggerTurn - get LLM to respond
+					);
+					fs.writeFileSync(triggerFile, ""); // Clear after reading
+				}
+			} catch {
+				// File might not exist yet
+			}
+		});
+
+		if (ctx.hasUI) {
+			ctx.ui.notify(`Watching ${triggerFile}`, "info");
+		}
+	});
+}