feat: add featured configs, seed data, and enhanced sorting

- Add featured field to configs table for curation
- Create 20 seed configs covering frontend, backend, DevOps, security, etc
- Add Featured badge to Explore page with subtle design
- Replace sort buttons with dropdown (Featured/Installs/This Week/New/Recent)
- Update landing page copy to be pain-focused
- Add trending (this week) and new (by created_at) sort options

Author: fullstackjam

migrations/0008_add_featured.sql

@@ -0,0 +1,2 @@
+-- Add featured flag to highlight curated configs on the explore page
+ALTER TABLE configs ADD COLUMN featured INTEGER DEFAULT 0;