fix: namespace rate limit buckets per endpoint, remove custom analytics

- Add `prefix` param to checkRateLimit/getRateLimitHeaders so each endpoint
  has its own bucket (previously all shared `admin_${ip}`, causing 429s when
  analytics/track incremented past n8n endpoints' lower limits)
- n8n/hardcover/currently-reading → prefix 'n8n-reading'
- n8n/status → prefix 'n8n-status'
- analytics/track → prefix 'analytics-track'
- Remove custom analytics system (AnalyticsProvider, lib/analytics,
  lib/useWebVitals, all /api/analytics/* routes) — was causing 500s in
  production due to missing PostgreSQL PageView table
- Remove analytics consent toggle from ConsentBanner/ConsentProvider

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/components/RootProviders.tsx

@@ -2,13 +2,6 @@
 
 import React, { useEffect, useState } from "react";
 
-// Lazy load providers to avoid webpack module resolution issues
-const AnalyticsProvider = React.lazy(() =>
-  import("@/components/AnalyticsProvider").then((mod) => ({
-    default: mod.AnalyticsProvider,
-  }))
-);
-
 const ToastProvider = React.lazy(() =>
   import("@/components/Toast").then((mod) => ({
     default: mod.ToastProvider,
@@ -38,14 +31,11 @@ export default function RootProviders({
 
   return (
     <React.Suspense fallback={<div className="relative z-10">{children}</div>}>
-      <AnalyticsProvider>
-        <ToastProvider>
-          <BackgroundBlobs />
-          <div className="relative z-10">{children}</div>
-          <ChatWidget />
-        </ToastProvider>
-      </AnalyticsProvider>
+      <ToastProvider>
+        <BackgroundBlobs />
+        <div className="relative z-10">{children}</div>
+        <ChatWidget />
+      </ToastProvider>
     </React.Suspense>
   );
 }
-