wiki: add Plex 4K codec guide and mdadm USB recovery; update yt-dlp, indexes

New articles:
- 04-streaming/plex/plex-4k-codec-compatibility.md
- 05-troubleshooting/storage/mdadm-usb-hub-disconnect-recovery.md

Updated:
- yt-dlp.md: Plex section and config reflect new HEVC auto-convert workflow
- SUMMARY.md, index.md, README.md, section indexes: 39 → 41 articles
- MajorWiki-Deploy-Status.md: count + date

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

05-troubleshooting/index.md

@@ -19,6 +19,9 @@ Practical fixes for common Linux, networking, and application problems.
 ## 🔒 SELinux
 - [SELinux: Fixing Dovecot Mail Spool Context (/var/vmail)](selinux-dovecot-vmail-context.md)
 
+## 💾 Storage
+- [mdadm RAID Recovery After USB Hub Disconnect](storage/mdadm-usb-hub-disconnect-recovery.md)
+
 ## 📝 Application Specific
 - [Obsidian Vault Recovery — Loading Cache Hang](obsidian-cache-hang-recovery.md)
 - [Gemini CLI Manual Update](gemini-cli-manual-update.md)