feat(server): runnable binary, Rune manifest, Docker image and CI

The HTTP server serves /healthz, the API namespace and the PWA, with the
frontend embedded behind a build tag so a clean checkout compiles without
a Node toolchain. /healthz reads the database rather than just answering:
a process that cannot reach its own data is not healthy, and a 200 there
would keep a broken container in rotation.

The image is distroless and static — the SQLite driver is pure Go, so
CGO stays off. The Rune manifest uses keep_entrypoint because there is
no shell in the image to run a startup command with, and its log watchers
match the JSON log format the container actually emits.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.github/workflows/ci.yml

@@ -0,0 +1,63 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+# A second push to the same branch makes the first run's result irrelevant.
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
+jobs:
+  go:
+    name: Go
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-go@v5
+        with:
+          go-version: "1.26"
+          cache: true
+
+      - name: Formatting
+        run: |
+          unformatted=$(gofmt -l .)
+          if [ -n "$unformatted" ]; then
+            echo "These files are not gofmt'd:"
+            echo "$unformatted"
+            exit 1
+          fi
+
+      - name: Vet
+        run: go vet ./...
+
+      # -race is the whole point of running tests in CI for a server with a
+      # WebSocket fan-out: a data race is exactly the bug that passes locally.
+      - name: Test
+        run: go test -race -count=1 ./...
+
+      - name: Build
+        run: CGO_ENABLED=0 go build ./...
+
+  docker:
+    name: Docker image builds
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: docker/setup-buildx-action@v3
+
+      # Build only — publishing happens on a tag, in release.yml. This job exists
+      # so a Dockerfile that no longer builds fails on the pull request rather
+      # than at release time.
+      - uses: docker/build-push-action@v6
+        with:
+          context: .
+          push: false
+          cache-from: type=gha
+          cache-to: type=gha,mode=max

.github/workflows/release.yml

@@ -0,0 +1,52 @@
+name: Release
+
+# Tagging is the release trigger: semver tags only, so a stray tag does not publish.
+on:
+  push:
+    tags: ["v[0-9]+.[0-9]+.[0-9]+*"]
+
+permissions:
+  contents: read
+  packages: write
+
+jobs:
+  image:
+    name: Build and publish image
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: docker/setup-qemu-action@v3
+      - uses: docker/setup-buildx-action@v3
+
+      - uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ghcr.io/${{ github.repository }}
+          # v1.4.2 publishes 1.4.2, 1.4 and 1 — so a Rune pinned to :1 gets
+          # patches without ever crossing a major version.
+          tags: |
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=semver,pattern={{major}}
+            type=raw,value=latest
+
+      # arm64 is not optional: a homelab is as likely to be a Raspberry Pi or an
+      # Apple silicon VM as it is to be an x86 box.
+      - uses: docker/build-push-action@v6
+        with:
+          context: .
+          platforms: linux/amd64,linux/arm64
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          build-args: |
+            VERSION=${{ github.ref_name }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max