fix: migrate to underscore-prefixed dirs, remove meta.yaml

- Content now at content/_<category>/ for Jekyll collections
- Removed meta.yaml — metadata lives in .md frontmatter only

Co-Authored-By: Paperclip <noreply@paperclip.ing>

Author: tallnato

content/_boombox/lo-fi-chill-beat.md

@@ -0,0 +1,10 @@
+---
+title: Lo-Fi Chill Beat
+author: Volts Community
+description: A relaxed lo-fi loop with mellow vibes, perfect for cruising. CC0 licensed placeholder.
+tags:
+  - ambient
+  - beats
+---
+
+A smooth lo-fi beat to set a relaxed mood. Ideal for late-night drives and chill sessions with your Boombox.