refactor: RAPPORT-HOST ist jetzt reines Backend

Das Frontend (Marketing + Login/Konto) ist in RAPPORT-WEBSITE umgezogen
(Hugo + Vanilla-JS). RAPPORT-HOST liefert dessen gebautes public/ statisch
aus und stellt /api bereit.

- server/index.js: serviert RAPPORT-WEBSITE/public + /api (eine Origin)
- server/env.js: websitePublicDir (WEBSITE_PUBLIC_DIR, Default Schwester-Repo);
  PUBLIC_BASE_URL Default auf einheitliche Origin :8787
- billing.js: Checkout-Redirects auf /konto/ bzw. /hosting-preise/
- entfernt: src/ (React), marketing/ (Hugo-Kopie), index.html, vite.config.js
- package.json: nur noch server/migrate/build:website-Scripts

E2E verifiziert: /, /hosting/, /login/, /konto/, /js + Font = 200;
register→checkout(mock)→Instanz; Redirect → /konto/?provisioned=1.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

server/routes/billing.js

@@ -61,7 +61,7 @@ billingRouter.post("/checkout", requireAuth, async (req, res) => {
         status: "active",
         periodEnd: new Date(Date.now() + 30 * 864e5),
       });
-      return res.json({ mock: true, url: `${env.publicBaseUrl}/dashboard?provisioned=1` });
+      return res.json({ mock: true, url: `${env.publicBaseUrl}/konto/?provisioned=1` });
     }
 
     // ── Stripe-Checkout-Session ──────────────────────────────────────────────
@@ -72,8 +72,8 @@ billingRouter.post("/checkout", requireAuth, async (req, res) => {
       customer_email: req.account.email,
       client_reference_id: req.account.id,
       metadata: { accountId: req.account.id, planId: plan.id },
-      success_url: `${env.publicBaseUrl}/dashboard?provisioned=1`,
-      cancel_url: `${env.publicBaseUrl}/plans?canceled=1`,
+      success_url: `${env.publicBaseUrl}/konto/?provisioned=1`,
+      cancel_url: `${env.publicBaseUrl}/hosting-preise/?canceled=1`,
     });
     res.json({ url: session.url });
   } catch (err) {