feat(cli): command architecture — agents, missions, gateway-aware prdy (#158)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

packages/cli/src/commands/with-auth.ts

@@ -0,0 +1,29 @@
+import type { AuthResult } from '../auth.js';
+
+export interface AuthContext {
+  gateway: string;
+  session: AuthResult;
+  cookie: string;
+}
+
+/**
+ * Load and validate the user's auth session.
+ * Exits with an error message if not signed in or session expired.
+ */
+export async function withAuth(gateway: string): Promise<AuthContext> {
+  const { loadSession, validateSession } = await import('../auth.js');
+
+  const session = loadSession(gateway);
+  if (!session) {
+    console.error('Not signed in. Run `mosaic login` first.');
+    process.exit(1);
+  }
+
+  const valid = await validateSession(gateway, session.cookie);
+  if (!valid) {
+    console.error('Session expired. Run `mosaic login` again.');
+    process.exit(1);
+  }
+
+  return { gateway, session, cookie: session.cookie };
+}