Add category filtering, default to copy mode, split dev/prod compose

- Default MOVE_MODE changed to copy so qBit can continue seeding
- Add QBIT_CATEGORY env var (default "Stash") to filter torrents
- Split compose into dev (build from source) and prod (pre-built image)
- Fix Dockerfile COPY glob needing trailing slash
- Update README and summary docs

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

docker-compose.prod.example.yaml

@@ -0,0 +1,22 @@
+services:
+  stash-handler:
+    image: git.fabledsword.com/bvandeusen/stashhandler:latest
+    container_name: stash-handler
+    restart: unless-stopped
+    environment:
+      QBIT_URL: "http://qbittorrent:8080"
+      QBIT_USERNAME: "admin"
+      QBIT_PASSWORD: "changeme"
+      STAGING_DIR: "/staging"
+      IMPORT_DIR: "/import"
+      DB_PATH: "/data/seen.db"
+      POLL_INTERVAL: "300"
+      MEDIA_EXTENSIONS: ".mp4,.mkv,.avi,.wmv,.mov,.webm,.flv,.m4v"
+      HASH_ALGORITHM: "sha256"
+      MOVE_MODE: "copy"
+      QBIT_CATEGORY: "Stash"
+      LOG_LEVEL: "INFO"
+    volumes:
+      - /data/staging:/staging:ro
+      - /data/stash-import:/import
+      - /data/stash-handler:/data