Update bundled yt-dlp and report source failures in chat

The image shipped a year-old yt-dlp, which YouTube now rejects with
"The page needs to be reloaded". Bumped to 2026.08.19 and documented
rebuilding as the standard fix, including how to pass a newer tag
without waiting for a repository update.

A downloader dying mid-stream also looked exactly like a very short
track: ffmpeg saw EOF, the player advanced, and the channel only got
"queue finished". The failure reason now reaches the chat.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Dockerfile

@@ -1,48 +1,51 @@
-# --- panel bundle -----------------------------------------------------------
-FROM node:22-bookworm-slim AS web
-WORKDIR /app/web
-COPY web/package.json web/package-lock.json* ./
-RUN npm install --no-audit --no-fund
-COPY web/ ./
-RUN npm run build
-
-# --- server dependencies ----------------------------------------------------
-# glibc image on purpose: @livekit/rtc-node ships prebuilt glibc binaries.
-FROM node:22-bookworm-slim AS deps
-WORKDIR /app
-COPY package.json package-lock.json* ./
-RUN npm install --omit=dev --no-audit --no-fund
-
-FROM node:22-bookworm-slim AS build
-WORKDIR /app
-COPY package.json package-lock.json* tsconfig.json ./
-RUN npm install --no-audit --no-fund
-COPY src/ ./src/
-RUN npm run build
-
-# --- runtime ----------------------------------------------------------------
-FROM node:22-bookworm-slim AS runtime
-ENV NODE_ENV=production
-# yt-dlp keeps its cache under $HOME; /app is not writable for the node user.
-ENV HOME=/tmp
-WORKDIR /app
-
-# yt-dlp_linux is a self-contained binary, so no Python runtime is needed.
-ARG YTDLP_VERSION=2025.08.20
-RUN apt-get update \
-    && apt-get install -y --no-install-recommends ca-certificates curl \
-    && curl -fsSL "https://github.com/yt-dlp/yt-dlp/releases/download/${YTDLP_VERSION}/yt-dlp_linux" -o /usr/local/bin/yt-dlp \
-    && chmod +x /usr/local/bin/yt-dlp \
-    && yt-dlp --version \
-    && apt-get purge -y curl \
-    && apt-get autoremove -y \
-    && rm -rf /var/lib/apt/lists/*
-
-COPY --from=deps /app/node_modules ./node_modules
-COPY --from=build /app/dist ./dist
-COPY --from=web /app/web/dist ./web/dist
-COPY package.json ./
-
-USER node
-EXPOSE 3005
-CMD ["node", "dist/index.js"]
+# --- panel bundle -----------------------------------------------------------
+FROM node:22-bookworm-slim AS web
+WORKDIR /app/web
+COPY web/package.json web/package-lock.json* ./
+RUN npm install --no-audit --no-fund
+COPY web/ ./
+RUN npm run build
+
+# --- server dependencies ----------------------------------------------------
+# glibc image on purpose: @livekit/rtc-node ships prebuilt glibc binaries.
+FROM node:22-bookworm-slim AS deps
+WORKDIR /app
+COPY package.json package-lock.json* ./
+RUN npm install --omit=dev --no-audit --no-fund
+
+FROM node:22-bookworm-slim AS build
+WORKDIR /app
+COPY package.json package-lock.json* tsconfig.json ./
+RUN npm install --no-audit --no-fund
+COPY src/ ./src/
+RUN npm run build
+
+# --- runtime ----------------------------------------------------------------
+FROM node:22-bookworm-slim AS runtime
+ENV NODE_ENV=production
+# yt-dlp keeps its cache under $HOME; /app is not writable for the node user.
+ENV HOME=/tmp
+WORKDIR /app
+
+# yt-dlp_linux is a self-contained binary, so no Python runtime is needed.
+# YouTube breaks extractors regularly, so keep this current: rebuilding with
+# --build-arg YTDLP_VERSION=<tag> (or bumping this default) is the usual fix for
+# "The page needs to be reloaded" and similar extraction errors.
+ARG YTDLP_VERSION=2026.08.19
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends ca-certificates curl \
+    && curl -fsSL "https://github.com/yt-dlp/yt-dlp/releases/download/${YTDLP_VERSION}/yt-dlp_linux" -o /usr/local/bin/yt-dlp \
+    && chmod +x /usr/local/bin/yt-dlp \
+    && yt-dlp --version \
+    && apt-get purge -y curl \
+    && apt-get autoremove -y \
+    && rm -rf /var/lib/apt/lists/*
+
+COPY --from=deps /app/node_modules ./node_modules
+COPY --from=build /app/dist ./dist
+COPY --from=web /app/web/dist ./web/dist
+COPY package.json ./
+
+USER node
+EXPOSE 3005
+CMD ["node", "dist/index.js"]