fix(scanner): handle watched moves across docker libraries

Emit transfer events when watcher reconciliation moves a book between libraries. Keep file-as-book and folder-as-book watcher paths consistent across Docker, direct runs, and delayed copy-delete moves.

Closes #386

docker-compose.yml

@@ -50,8 +50,10 @@ services:
     healthcheck:
       test:
         [
-          "CMD-SHELL",
-          'node -e "fetch(''http://127.0.0.1:''+(process.env.PORT||3000)+''/api/v1/health'').then(r=>process.exit(r.ok?0:1)).catch(()=>process.exit(1))"',
+          "CMD",
+          "node",
+          "-e",
+          "const p=process.env.PORT||3000;fetch('http://127.0.0.1:'+p+'/api/v1/health').then(r=>process.exit(r.ok?0:1)).catch(()=>process.exit(1))",
         ]
       interval: 30s
       timeout: 5s