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/lib/seo.ts

@@ -0,0 +1,50 @@
+import { locales } from '@/i18n';
+
+export const primaryDomain =
+    process.env.NEXT_PUBLIC_APP_URL || 'https://skills.palebluedot.live';
+
+const DEFAULT_LOCALE = 'en';
+
+/** 
+ * Get canonical URL path for a locale 
+ * (no prefix for default locale, matching localePrefix: 'as-needed')
+ */
+export function getCanonicalPath(locale: string, route: string): string {
+    // Normalize route to always start with a slash and not end with a slash
+    let formattedRoute = route;
+    if (!formattedRoute.startsWith('/')) {
+        formattedRoute = `/${formattedRoute}`;
+    }
+    if (formattedRoute.length > 1 && formattedRoute.endsWith('/')) {
+        formattedRoute = formattedRoute.slice(0, -1);
+    }
+
+    if (locale === DEFAULT_LOCALE) {
+        if (formattedRoute === '/') return '';
+        return formattedRoute;
+    }
+
+    if (formattedRoute === '/') return `/${locale}`;
+    return `/${locale}${formattedRoute}`;
+}
+
+/**
+ * Generate Next.js alternates metadata for a specific route
+ * @param locale Current active locale
+ * @param route The route path (e.g. '/about', '/categories')
+ */
+export function getPageAlternates(locale: string, route: string) {
+    // Ensure we fall back to / if it's empty
+    const canonicalPath = getCanonicalPath(locale, route) || '/';
+
+    const languages: Record<string, string> = {};
+
+    for (const l of locales) {
+        languages[l] = `${primaryDomain}${getCanonicalPath(l, route) || '/'}`;
+    }
+
+    return {
+        canonical: `${primaryDomain}${canonicalPath}`,
+        languages,
+    };
+}