fix: session cookie over plain http, console onboarding gate, webkit qa coverage

- the session cookie was Secure whenever NODE_ENV=production, so a production build on http://localhost got no cookie back in Safari: every page after signup looked signed-out. It is now Secure only when X-Forwarded-Proto says https, or when COOKIE_SECURE=1.
- /app and /app/[id] now require an analyst and a Jev key, the same rule /api/analyze enforces with a 412. Closing the guide mid-way used to leave a console that could not run anything.
- Playwright runs the production server (pree2e builds first) and gains a webkit project for session survival; chromium-only QA could never see a Secure-cookie rejection.
- tests-e2e/session.spec.ts pins both; .env.example gains COOKIE_SECURE and stops shipping a blank APP_SECRET.
- e2e: 21 passed (setup, chromium, webkit, mobile).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

package.json

@@ -8,7 +8,8 @@
     "start": "next start",
     "lint": "eslint",
     "test": "node --no-warnings --test tests/*.test.ts",
-    "e2e": "playwright test"
+    "e2e": "playwright test",
+    "pree2e": "npm run build"
   },
   "dependencies": {
     "@openuidev/lang-core": "^0.3.0",
@@ -29,4 +30,4 @@
     "eslint-config-next": "16.3.5",
     "typescript": "^5"
   }
-}
+}