wiki: add firewalld mail ports reset article + session updates

- New article: firewalld mail ports wiped after reload (IMAP + webmail outage)
- New article: Plex 4K codec compatibility (Apple TV)
- New article: mdadm RAID recovery after USB hub disconnect
- Updated yt-dlp article
- Updated all index files: SUMMARY.md, index.md, README.md, category indexes
- Article count: 41 → 42

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

MajorWiki-Deploy-Status.md

@@ -31,7 +31,7 @@ DNS record and Caddy entry have been removed.
 
 ## Content
 
-- 39 articles across 5 domains
+- 42 articles across 5 domains
 - Source of truth: `MajorVault/20-Projects/MajorTwin/08-Wiki/`
 - Deployed via Gitea webhook (push from MajorAir → auto-pull on majorlab)
 
@@ -63,7 +63,7 @@ rsync -av --include="*.md" --include="*/" --exclude="*" \
 
 ---
 
-*Updated 2026-03-14*
+*Updated 2026-03-15*
 
 ## Canonical Update Workflow