ci: build and release webdrop-api and webdrop-files as separate images [CI]

- dev images are built only when the push touched code that image uses (path filters);
  webdrop-files does not wait for the frontend build
- one v* tag releases both images (:tag and :latest) after the shared checks
- registry build and push live in scripts/ci-publish-image.sh, used by every workflow
- containers: fix the api Containerfile (missing Sync project), add Containerfile.files,
  Quadlet units for the file service (prod and dev), env examples, and registry
  auto-update for the production units so each machine pulls only the image it runs

deploy/webdrop-files.container

@@ -0,0 +1,31 @@
+[Unit]
+Description=WebDrop file service (fileAPI)
+Wants=network-online.target
+After=network-online.target
+
+[Container]
+ContainerName=webdrop-files
+# 正式环境:跟踪打 v* tag 发布的 latest。放文件的机器(例如家里的 NAS)只拉这个镜像,不需要主后端的
+Image=registry.oeo.one/justme/webdrop-files:latest
+Pull=missing
+AutoUpdate=registry
+PublishPort=127.0.0.1:5100:5100
+Environment=ASPNETCORE_URLS=http://+:5100
+Environment=FileApi__DataDir=/data
+Environment=DOTNET_EnableDiagnostics=0
+# 和主后端共用的密钥、允许的页面来源、备份设置等,不进仓库。例子见 webdrop-files.env.example
+EnvironmentFile=%h/podman/webdrop-files/webdrop-files.env
+Volume=%h/podman/webdrop-files/data:/data:Z,U
+ReadOnly=true
+ReadOnlyTmpfs=false
+Tmpfs=/tmp:rw,noexec,nosuid,size=16m
+DropCapability=ALL
+NoNewPrivileges=true
+
+[Service]
+Restart=always
+TimeoutStartSec=120
+TimeoutStopSec=60
+
+[Install]
+WantedBy=default.target