User management: signing in is required before anything is loaded, the sign-in screen is drawn in the same canvas (user name, password as bullets, Enter moves on and submits) and the editor is built only after it; the API gained auth/session, auth/login and auth/logout while every other route answers 401 without a session, projects carry an owner and a foreign one comes back as 404, accounts live in data/users.json with a password hash and sessions as files in data/sessions with a sliding 30 days, so a build under the open tab does not sign anybody out; Logout sits at the far right of the toolbar and, as asked in the issue, does not reload the page: Editor.dispose() takes the editor down while the canvas stays, which is why the autosave, the focus handlers, the window listeners of the tilemap panel, the shortcuts and the plugins all got a way back; the tools sign in as e2e (tools/lib/auth.mjs, password from GAME_MAKER_E2E_PASSWORD or the git-ignored data/e2e-password.txt) and the browser gets the same session by cookie, new e2e module 45 covers the screen, the wrong pair, the bullets, logout without a reload and signing in again, new unit tests for HttpAuthStore and for what a session leaves behind (#177)

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tools/e2e/index.mjs

@@ -47,6 +47,7 @@ import { physics } from './41-physics.mjs';
 import { shapes } from './42-shapes.mjs';
 import { queries } from './43-queries.mjs';
 import { documents } from './44-documents.mjs';
+import { login } from './45-login.mjs';
 
 export const STEPS = [
   hierarchy,
@@ -93,4 +94,5 @@ export const STEPS = [
   shapes,
   queries,
   documents,
+  login,
 ];