TrueNAS SCALE deployment: GHCR image publishing + pull-only compose

TrueNAS custom apps cannot build: the main compose's 'build: .' (plus
relative .env/bind mounts) fails app 'up'. Added a GitHub Actions
workflow publishing ghcr.io/fez5587/momentum-app on every master push,
and deploy/docker/truenas-compose.yml — a pull-only variant with
dataset host-paths, inline environment (secrets as <FILL-ME>
placeholders, current validated strategy knobs pre-filled), and the
same healthchecks. Validated with docker compose config.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.github/workflows/docker.yml

@@ -0,0 +1,34 @@
+name: docker-image
+
+# Build + push the app image to GHCR on every master push, so pull-only
+# hosts (TrueNAS SCALE custom apps) can deploy without a repo checkout.
+on:
+  push:
+    branches: [master]
+    paths:
+      - "Dockerfile"
+      - "requirements.txt"
+      - "**.py"
+      - ".github/workflows/docker.yml"
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+    steps:
+      - uses: actions/checkout@v4
+      - uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - uses: docker/build-push-action@v6
+        with:
+          context: .
+          push: true
+          tags: |
+            ghcr.io/fez5587/momentum-app:latest
+            ghcr.io/fez5587/momentum-app:${{ github.sha }}