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/ClientProviders.tsx

@@ -5,8 +5,7 @@ import { usePathname } from "next/navigation";
 import dynamic from "next/dynamic";
 import { ToastProvider } from "@/components/Toast";
 import ErrorBoundary from "@/components/ErrorBoundary";
-import { AnalyticsProvider } from "@/components/AnalyticsProvider";
-import { ConsentProvider, useConsent } from "./ConsentProvider";
+import { ConsentProvider } from "./ConsentProvider";
 import { ThemeProvider } from "./ThemeProvider";
 import { motion, AnimatePresence } from "framer-motion";
 
@@ -97,12 +96,7 @@ function GatedProviders({
   mounted: boolean;
   is404Page: boolean;
 }) {
-  const { consent } = useConsent();
-
-  // If consent is not decided yet, treat optional features as off
-  const analyticsEnabled = !!consent?.analytics;
-
-  const content = (
+  return (
     <ErrorBoundary>
       <ToastProvider>
         {mounted && <BackgroundBlobs />}
@@ -110,6 +104,4 @@ function GatedProviders({
       </ToastProvider>
     </ErrorBoundary>
   );
-
-  return analyticsEnabled ? <AnalyticsProvider>{content}</AnalyticsProvider> : content;
 }