feat: complete launch & marketing layer

- Add marketing pages: blog, changelog, roadmap, waitlist, security, maintenance
- Add GDPR cookie consent banner with preference modal
- Add referral system with API routes for code generation/tracking
- Add waitlist API with referral support
- Add PWA support: manifest, service worker, install prompt
- Add onboarding flow with 6-step guided tour
- Add in-app notification center with bell dropdown
- Add admin launch checklist (32 items across 8 categories)
- Update landing page with trust badges
- Add Open Graph image and favicon
- Configure ESLint for PWA install patterns
- Add LAUNCH_CHECKLIST.md with go-to-market guide

Supabase migrations for:
- blog_posts and blog_categories tables
- waitlist_signups table
- roadmap_items table
- launch_checklist_items table

eslint.config.mjs

@@ -13,6 +13,13 @@ const eslintConfig = defineConfig([
     "build/**",
     "next-env.d.ts",
   ]),
+  // Allow setState in useEffect for PWA prompts and client-side state initialization
+  {
+    files: ["**/pwa/**", "**/InstallPrompt.tsx"],
+    rules: {
+      "react-hooks/set-state-in-effect": "off",
+    },
+  },
 ]);
 
 export default eslintConfig;