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

src/app/api/v1/referrals/route.ts

@@ -0,0 +1,127 @@
+// Referrals API - Route-based handlers
+import { NextRequest, NextResponse } from "next/server";
+import { z } from "zod";
+import { apiLimiter, checkRateLimit, rateLimitExceeded, securityHeaders } from "@/lib/rate-limit";
+import { analytics } from "@/lib/analytics";
+import { captureError } from "@/lib/sentry";
+
+// Helper functions
+function apiResponse(data: unknown, status: number = 200) {
+  return NextResponse.json({ data }, { status });
+}
+
+function apiError(message: string, status: number) {
+  return NextResponse.json({ error: message }, { status });
+}
+
+function validationError(error: z.ZodError) {
+  return NextResponse.json({ error: "Validation failed", details: error.issues }, { status: 400 });
+}
+
+// ============================================
+// REFERRAL API
+// ============================================
+
+const createReferralSchema = z.object({
+  brand_id: z.string().uuid(),
+  referred_email: z.string().email(),
+  referral_code: z.string().min(6).max(50),
+});
+
+export async function POST(req: NextRequest) {
+  try {
+    // Rate limiting
+    const rateCheck = await checkRateLimit(apiLimiter, req.headers.get("x-forwarded-for") || "anonymous");
+    if (!rateCheck.success) {
+      return rateLimitExceeded(Math.ceil((rateCheck.reset - Date.now()) / 1000));
+    }
+
+    const body = await req.json();
+    const validation = createReferralSchema.safeParse(body);
+    
+    if (!validation.success) {
+      return validationError(validation.error);
+    }
+
+    const supabaseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL!;
+    const serviceKey = process.env.SUPABASE_SERVICE_ROLE_KEY!;
+
+    // Redeem referral via RPC
+    const res = await fetch(
+      `${supabaseUrl}/rest/v1/rpc/redeem_referral`,
+      {
+        method: "POST",
+        headers: {
+          apikey: serviceKey,
+          "Content-Type": "application/json",
+          Prefer: "return=representation",
+        },
+        body: JSON.stringify({
+          p_brand_id: validation.data.brand_id,
+          p_referred_email: validation.data.referred_email,
+          p_referral_code: validation.data.referral_code,
+        }),
+      }
+    );
+
+    if (!res.ok) {
+      const error = await res.json();
+      return apiError(error.message || "Failed to redeem referral", 500);
+    }
+
+    const referral = await res.json();
+    
+    analytics.referralCompleted(validation.data.referral_code, referral.referred_user_id);
+
+    return apiResponse(referral, 201);
+  } catch (error) {
+    captureError(error as Error, { path: "/api/referrals", method: "POST" });
+    return apiError("Internal server error", 500);
+  }
+}
+
+export async function GET(req: NextRequest) {
+  try {
+    const { searchParams } = new URL(req.url);
+    const brand_id = searchParams.get("brand_id");
+
+    if (!brand_id) {
+      return apiError("brand_id is required", 400);
+    }
+
+    const supabaseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL!;
+    const anonKey = process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!;
+
+    const res = await fetch(
+      `${supabaseUrl}/rest/v1/referral_codes?brand_id=eq.${brand_id}&select=*&order=created_at.desc`,
+      {
+        headers: {
+          apikey: anonKey,
+          "Content-Type": "application/json",
+        },
+      }
+    );
+
+    if (!res.ok) {
+      return apiError("Failed to fetch referrals", 500);
+    }
+
+    const referrals = await res.json();
+    return apiResponse(referrals);
+  } catch (error) {
+    captureError(error as Error, { path: "/api/referrals", method: "GET" });
+    return apiError("Internal server error", 500);
+  }
+}
+
+// OPTIONS handler
+export async function OPTIONS() {
+  return new Response(null, {
+    status: 204,
+    headers: {
+      ...securityHeaders(),
+      "Access-Control-Allow-Methods": "GET, POST, OPTIONS",
+      "Access-Control-Allow-Headers": "Content-Type, Authorization",
+    },
+  });
+}