fix(backend): YouTube downloads — install Deno + pull yt-dlp nightly

Downloads were 403ing on two fronts: (1) recent yt-dlp needs a JS runtime to
solve YouTube's signature/nsig challenge (Deno, added in cb7a3d7), and (2) the
current yt-dlp *stable* had a bug that 403'd the android_vr client on every video
(yt-dlp#17456, fixed in nightly). Switch the backend from the stable yt-dlp
binary to nightly via pip (`--pre 'yt-dlp[default]'`). Verified end-to-end incl.
a real frontend download. No cookies / PO-token service / proxy needed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

CHANGELOG.md

@@ -64,6 +64,23 @@ Versioning: two-part `MAJOR.MINOR` — each release bumps the minor (features an
 
 ---
 
+## [2.2] — 2026-08-19
+
+Gets YouTube downloads working again after they broke on two independent fronts.
+
+### Fixed
+- **YouTube downloads (HTTP 403 + "Signature solving failed")** — two things had broken downloads:
+  1. Recent yt-dlp needs an **external JavaScript runtime** to solve YouTube's signature/nsig
+     challenge — without it, formats were skipped and the media 403'd. The backend now installs
+     **Deno**, which yt-dlp uses automatically.
+  2. A bug in the current yt-dlp **stable** 403'd the `android_vr` client on *every* video
+     ([yt-dlp#17456](https://github.com/yt-dlp/yt-dlp/issues/17456), fixed in nightly). The backend
+     now pulls yt-dlp from the **nightly** channel (`pip install --pre 'yt-dlp[default]'`).
+  No cookies, PO-token service, or proxy needed — the earlier 403 that looked like an IP block was
+  this stable bug.
+
+---
+
 ## [2.1] — 2026-08-14
 
 Builds on the 2.0 listening archive with a **head-to-head "Musik-Match"**, brings the **artist pin**

docker-compose.yml

@@ -36,7 +36,7 @@ services:
     command: >
       sh -c "
         apt-get update && apt-get install -y --no-install-recommends python3 python3-pip ffmpeg curl git unzip && rm -rf /var/lib/apt/lists/* &&
-        curl -sL https://github.com/yt-dlp/yt-dlp/releases/latest/download/yt-dlp -o /usr/local/bin/yt-dlp && chmod a+rx /usr/local/bin/yt-dlp &&
+        pip install --break-system-packages -U --pre 'yt-dlp[default]' &&
         curl -fsSL https://deno.land/install.sh | sh &&
         pip install --break-system-packages spotapi 'git+https://github.com/TzurSoffer/spotify-downloader' &&
         mkdir -p /deps && cd /deps && npm install express kuromoji &&