Initial scaffold: blob store server, CLI scripts, and PWA share target

Clipboard/screenshot sync across own devices via a single DEVICE_TOKEN-gated
blob store, plus a small installable web app so a phone can push/pull
clips and share screenshots via the OS share sheet.

docker-compose.yml

@@ -0,0 +1,20 @@
+services:
+  app:
+    image: ${IMAGE}
+    container_name: scrot
+    restart: unless-stopped
+    pull_policy: always
+    ports:
+      - "${HOST_PORT:-3041}:3000"
+    environment:
+      - CLIP_TTL_SECONDS=${CLIP_TTL_SECONDS:-86400}
+      - SHOT_TTL_SECONDS=${SHOT_TTL_SECONDS:-1209600}
+      - MAX_UPLOAD_BYTES=${MAX_UPLOAD_BYTES:-52428800}
+      - DEVICE_TOKEN=${DEVICE_TOKEN}
+    volumes:
+      # Named volume, not a bind mount into the build context — the SQLite
+      # DB and blob bytes live here and must survive image redeploys.
+      - scrot-data:/app/data
+
+volumes:
+  scrot-data: