sync: add AI review pipeline, parallel skill-files fetch, Redis cache improvements

- feat(review): add skill_reviews table, review API endpoints (pending/submit/stats), admin auth
- perf: parallel file fetching in skill-files API (was sequential → timeout)
- fix: handle Date serialization from Redis cache
- fix: align curation batch scripts with current browseReadyFilter

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

scripts/curation/batch-score.mjs

@@ -285,7 +285,6 @@ async function main() {
     FROM skills
     WHERE is_blocked = false
       AND is_duplicate = false
-      AND (skill_type IS NULL OR skill_type IN ('standalone', 'collection'))
       AND quality_score IS NULL
       AND raw_content IS NOT NULL
   `);
@@ -305,7 +304,7 @@ async function main() {
       FROM skills
       WHERE is_blocked = false
         AND is_duplicate = false
-        AND (skill_type IS NULL OR skill_type IN ('standalone', 'collection'))
+        AND is_duplicate = false
         AND quality_score IS NULL
         AND raw_content IS NOT NULL
       ORDER BY github_stars DESC NULLS LAST
@@ -334,7 +333,7 @@ async function main() {
       FROM skills
       WHERE is_blocked = false
         AND is_duplicate = false
-        AND (skill_type IS NULL OR skill_type IN ('standalone', 'collection'))
+        AND is_duplicate = false
         AND quality_score IS NULL
         AND raw_content IS NOT NULL
       ORDER BY github_stars DESC NULLS LAST