feat: add apps/p2 (imported from pi-private at 7dadff697)

p2 (Pi Mobile on Chord v2) moves from pi-private into pi as one commit. Root scripts that loop all workspaces
use --if-present; npm test, ./test.sh and the release script cover packages/* only (p2: cd apps/p2 && npm test);
sync-versions also updates apps' workspace pins.

apps/p2/plugins/envs/worker.ts

@@ -0,0 +1,36 @@
+import { contribute, defineFacet } from "@p2/app/v1";
+import { HarnessEnvironments, workerOf } from "@p2/app/v1/worker";
+import { loadEnvs } from "./config.ts";
+import { remoteSession } from "./remote-env.ts";
+import { EnvStore } from "./store.ts";
+
+export default defineFacet((host) => {
+	contribute(host, "p2.worker-envs", (self) => {
+		const worker = workerOf(self);
+		self.open(
+			async () => {
+				const store = new EnvStore(worker().init.dataDir);
+				await store.observer.start();
+				return store;
+			},
+			(store) => store.observer.close(),
+		);
+		self.contribute(HarnessEnvironments, {
+			remote: {
+				open: async (env) => {
+					const { dataDir } = worker().init;
+					const configs = await loadEnvs(dataDir);
+					const config = Object.hasOwn(configs, env) ? configs[env] : undefined;
+					if (!config) throw new Error(`Environment "${env}" is not configured; refusing local execution`);
+					// One connection for every conversation working on this environment, at its directories.
+					const remote = remoteSession(dataDir, env, config, "/");
+					return { at: remote.at, close: () => remote.connection.close() };
+				},
+				host: async (env) => {
+					const configs = await loadEnvs(worker().init.dataDir);
+					return Object.hasOwn(configs, env) ? configs[env]?.host : undefined;
+				},
+			},
+		});
+	});
+});