Replace legacy FTP dependency and add CI

.github/workflows/docker.yml

@@ -0,0 +1,20 @@
+name: Docker Build
+
+on:
+  push:
+    branches:
+      - master
+      - main
+      - codex/**
+  pull_request:
+
+jobs:
+  docker-test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Build test image
+        run: docker build --target test -t virtualfs:test .