refactor(docker): default compose builds from Dockerfiles (baked deps, cached)

Chosen flow: build on the host from backend/scrobble Dockerfiles instead of
pulling from a registry (no registry / no Docker-on-dev needed). Heavy deps are
baked, so restarts are instant and rebuilds after git pull are cache-fast.
Removed the now-obsolete docker-compose.dev.yml (runtime-install variant); the
optional push-to-registry script stays for a future CI flow. Updated README,
CLAUDE.md, .env.example.

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

docker-compose.dev.yml

@@ -1,75 +0,0 @@
-services:
-
-  # ── Frontend (nginx) ──────────────────────────────────────────────────────────
-  novasonic-frontend:
-    build: .
-    container_name: novasonic-frontend
-    restart: unless-stopped
-    ports:
-      - "8080:80"          # route this port through your reverse proxy
-    environment:
-      - NAVIDROME_URL=${NAVIDROME_URL}   # pre-filled on the setup screen
-      - BACKEND_URL=${BACKEND_URL}       # pre-filled on the setup screen
-      - SCROBBLE_URL=${SCROBBLE_URL}     # play-log / stats service (setup screen)
-
-  # ── Backend (yt-dlp download server) ─────────────────────────────────────────
-  novasonic-backend:
-    image: node:22-slim
-    container_name: novasonic-backend
-    restart: unless-stopped
-    working_dir: /app
-    volumes:
-      - ./backend:/app:ro                # mount entire backend dir (server + lib/)
-      - ${MUSIC_PATH}:${MUSIC_PATH}      # exact path from .env, no remapping
-      - novasonic-data:/data             # writable data dir for overrides, state, etc.
-    ports:
-      - "3700:3700"                      # route this port through your reverse proxy
-    environment:
-      - PORT=3700
-      - MUSIC_PATH=${MUSIC_PATH}         # same path inside the container
-      - DATA_PATH=/data
-      - AUDIO_FMT=${AUDIO_FMT:-mp3}
-      - AUDIO_QUALITY=${AUDIO_QUALITY:-0}
-      - MAX_PARALLEL=${MAX_PARALLEL:-2}
-      - DOWNLOAD_BACKEND=${DOWNLOAD_BACKEND:-ytdlp}
-      - TICKETMASTER_API_KEY=${TICKETMASTER_API_KEY}
-      # Android APK download button — backend proxies a fixed Gitea release ("apk-latest"), same LAN.
-      # Optional: leave unset to use the local /data/novasonic.apk fallback instead.
-      - GITEA_URL=${GITEA_URL:-}                 # internal Gitea base, e.g. http://gitea:3000
-      - GITEA_REPO=${GITEA_REPO:-}               # owner/repo, e.g. Docker/NovaSonic
-      - GITEA_TOKEN=${GITEA_TOKEN:-}             # read token (only for a private repo)
-      - GITEA_APK_TAG=${GITEA_APK_TAG:-apk-latest}
-    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/* &&
-        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 &&
-        cd /app && PATH=/root/.deno/bin:$$PATH NODE_PATH=/deps/node_modules node novasonic-server.js
-      "
-
-  # ── Scrobble service (isolated timestamped play-log → stats + Wrapped) ────────
-  novasonic-scrobble:
-    image: node:22-slim
-    container_name: novasonic-scrobble
-    restart: unless-stopped
-    working_dir: /app
-    volumes:
-      - ./scrobble:/app:ro               # server code (read-only)
-      - novasonic-scrobble-data:/data    # own DB volume, isolated from downloads
-    ports:
-      - "3710:3710"                      # route this port through your reverse proxy
-    environment:
-      - PORT=3710
-      - DATA_PATH=/data
-      - NAVIDROME_URL=${NAVIDROME_URL}   # for ping.view auth verification
-    command: >
-      sh -c "
-        mkdir -p /deps && cd /deps && npm install express &&
-        cd /app && NODE_PATH=/deps/node_modules node --experimental-sqlite scrobble-server.js
-      "
-
-volumes:
-  novasonic-data:          # persistent storage for romaji overrides and app state
-  novasonic-scrobble-data: # persistent play-log DB (novasonic-plays.db)