docs: sync local vault content to remote

Update index pages, troubleshooting articles, README, and deploy status
to match current local vault state.

05-troubleshooting/yt-dlp-fedora-js-challenge.md

@@ -135,3 +135,42 @@ This is a YouTube-side experiment. yt-dlp falls back to other clients automatica
 yt-dlp --version
 pip show yt-dlp
 ```
+
+### Format Not Available: Strict AVC+M4A Selector
+
+The format selector `bestvideo[vcodec^=avc]+bestaudio[ext=m4a]` will hard-fail if YouTube doesn't serve H.264 (AVC) video for a given video:
+
+```
+ERROR: [youtube] Requested format is not available. Use --list-formats for a list of available formats
+```
+
+This is separate from the n-challenge issue — the format simply doesn't exist for that video (common with newer uploads that are VP9/AV1-only).
+
+**Fix 1 — Relax the selector to mp4 container without enforcing codec:**
+
+```bash
+yt-dlp -f 'bestvideo[ext=mp4]+bestaudio[ext=m4a]/bestvideo+bestaudio' \
+  --merge-output-format mp4 \
+  -o "/plex/plex/%(title)s.%(ext)s" \
+  --write-auto-subs --embed-subs \
+  https://youtu.be/VIDEO_ID
+```
+
+**Fix 2 — Let yt-dlp pick best and re-encode to H.264 via ffmpeg (Plex-safe, slower):**
+
+```bash
+yt-dlp -f 'bestvideo+bestaudio' \
+  --merge-output-format mp4 \
+  --recode-video mp4 \
+  -o "/plex/plex/%(title)s.%(ext)s" \
+  --write-auto-subs --embed-subs \
+  https://youtu.be/VIDEO_ID
+```
+
+Use `--recode-video mp4` when Plex direct play is required and the source stream may be VP9/AV1. Requires ffmpeg.
+
+**Inspect available formats first:**
+
+```bash
+yt-dlp --list-formats https://youtu.be/VIDEO_ID
+```