sync: SEO canonical URLs, curation improvements, batch scripts, stats fix

- Dynamic canonical URLs and alternates for all pages (SEO fix)
- Shared seo.ts utility for canonical path generation
- Improved duplicate detection: standalone > aggregator priority, forks/created_at tie-breakers
- browseReadyFilter now includes unique aggregator skills
- Stats aligned with browseReadyFilter (was showing 16k instead of 62k+)
- Re-review mechanism: content_hash changes trigger needs-re-review
- review_status field added to skills schema
- Batch security scan and quality score scripts
- Indexer Dockerfile updated for curation deps
- Removed roadmap from README

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

apps/web/app/[locale]/claude-plugin/page.tsx

@@ -1,4 +1,5 @@
 import { getTranslations, setRequestLocale } from 'next-intl/server';
+import { getPageAlternates } from '@/lib/seo';
 import Link from 'next/link';
 import type { Metadata } from 'next';
 import {
@@ -31,6 +32,7 @@ export async function generateMetadata({
   return {
     title: t('metadata.title'),
     description: t('metadata.description'),
+    alternates: getPageAlternates(locale, '/claude-plugin'),
     openGraph: {
       title: t('metadata.title'),
       description: t('metadata.description'),