fix(docker): let SELinux hosts read the bind-mounted checkout (#1391)

Allow the Docker checkout bind mount on SELinux hosts.

Contribution by @anilguvenc.

README.md

@@ -207,6 +207,8 @@ env UID=1026 GID=100 docker compose up -d
 
 Keep the `env`: bash treats `UID` as read-only, so a plain `UID=1026` in front of a command is silently ignored. If the container can't write the checkout, it says so at start. Docker Desktop on macOS and Windows maps ownership for you.
 
+On SELinux hosts (Fedora, RHEL), compose mounts the checkout with `:z` so the container may read it; Docker may relabel the checkout for container access, which can take a moment on a large checkout. Without that, the start fails with `Cannot find module '/app/scripts/docker-start.mjs'`.
+
 Behind a reverse proxy, put your keys in `.env` or pass them as environment variables - Provider Settings refuses proxied requests on purpose - and add the hostname you serve it on, for example `GEV_ALLOWED_HOSTS=globe.example.lan` (see [Sharing an instance](#-sharing-an-instance)).
 
 </details>

changelog.d/1391-docker-selinux.md

@@ -0,0 +1,4 @@
+- Start the Docker install on SELinux hosts such as Fedora and RHEL. Compose now
+  mounts the checkout with `:z`; without it the container could not read `/app`
+  and stopped with "Cannot find module '/app/scripts/docker-start.mjs'"
+  (Anıl Güvenç, @anilguvenc, #1391).

compose.yaml

@@ -22,5 +22,8 @@ services:
       # UI land in the .env on your host instead of vanishing with the
       # container. node_modules stays in the image: sharp and friends are
       # compiled for Linux and must not be shadowed by a host install.
-      - .:/app
+      # `:z` relabels the checkout for containers on SELinux hosts (Fedora,
+      # RHEL); without it the container cannot read /app at all and Node
+      # reports the launcher as "Cannot find module". Elsewhere it is ignored.
+      - .:/app:z
       - /app/node_modules

docs/CURRENT-STATE.md

@@ -1,5 +1,9 @@
 # God's Eye View Current State
 
+Docker Compose mounts the checkout with the shared SELinux `:z` label so
+containers can read it on enforcing SELinux hosts. The separate image-owned
+`node_modules` volume and loopback-only port publishing remain unchanged.
+
 Aircraft detection candidates reuse normalized display text until callsign or
 registration changes, including in-place enrichment. Each candidate resolves its
 fleet model once per collection. Positions, model ownership and tracked-aircraft

src/dockerLauncher.test.mjs

@@ -75,4 +75,5 @@ test('the Docker install path keeps its loopback-only, launcher-owned contract',
   assert.match(compose, /^\s+- GEV_KEY_SETUP_TRUSTED_PEERS$/m, 'the operator policy reaches the launcher without a hard-coded address');
   assert.match(compose, /^\s+- GEV_ALLOWED_HOSTS$/m, 'the host allowlist reaches Vite');
   assert.doesNotMatch(compose, /network_mode/, 'the container keeps its own network namespace');
+  assert.match(compose, /^\s+- \.:\/app:z$/m, 'SELinux hosts can read the bind-mounted checkout');
 });