Add DRM downloads, scrapers, gallery index, and UI improvements

- DRM video download pipeline with pywidevine subprocess for Widevine key acquisition
- Scraper system: forum threads, Coomer/Kemono API, and MediaLink (Fapello) scrapers
- SQLite-backed media index for instant gallery loads with startup scan
- Duplicate detection and gallery filtering/sorting
- HLS video component, log viewer, and scrape management UI
- Dockerfile updated for Python/pywidevine, docker-compose volume for CDM

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

Dockerfile

@@ -8,7 +8,8 @@ RUN cd client && npm run build
 
 # Stage 2 — Production
 FROM node:20-alpine
-RUN apk add --no-cache ffmpeg openssl
+RUN apk add --no-cache ffmpeg openssl python3 py3-pip \
+    && pip3 install --break-system-packages pywidevine
 WORKDIR /app
 COPY server/package*.json ./server/
 RUN cd server && npm install --production