ci: build & publish app + bot images to Gitea registry on merge

Add a Gitea Actions workflow (.gitea/workflows/build-images.yml) that fires on
push to main (and workflow_dispatch). On the always-on ubuntu-latest runner it:

  - verifies the host Docker daemon is reachable (socket must be mounted)
  - logs into gitea.whitlocktech.com with a PAT (REGISTRY_USER / REGISTRY_TOKEN)
  - builds & pushes both images from the existing Dockerfiles, each tagged
    :latest and :sha-<7>:
      gitea.whitlocktech.com/<owner>/website-app  (./Dockerfile — server+client)
      gitea.whitlocktech.com/<owner>/website-bot   (./bot/Dockerfile)

Raw docker CLI (no marketplace actions) for portability on self-hosted Gitea;
the shared host daemon gives free layer caching between runs. Registry owner is
lowercased for Docker refs. Deploy (compose image: + pull) is a follow-up.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0114TpmrNW4wNXsHq5CR72jQ

.gitea/workflows/build-images.yml

@@ -0,0 +1,87 @@
+# Build and publish the app + bot container images to Gitea's container registry
+# on every merge to main. Production then pulls prebuilt images instead of
+# building on the host.
+#
+# Prerequisites (one-time):
+#   • An always-on Gitea runner with label `ubuntu-latest` whose jobs have the
+#     host Docker socket mounted (/var/run/docker.sock), so `docker build` talks
+#     to the host daemon. This also gives free layer caching between runs.
+#   • Two repo secrets (Settings → Actions → Secrets):
+#       REGISTRY_USER  — the Gitea username that owns the token below
+#       REGISTRY_TOKEN — a Gitea access token with `write:package` (+ read:package)
+#     See the PR description / README for step-by-step token creation.
+#
+# Produces, in gitea.whitlocktech.com/<owner>/ :
+#   website-app:latest  + website-app:sha-<7>
+#   website-bot:latest  + website-bot:sha-<7>
+
+name: Build container images
+
+on:
+  push:
+    branches: [main]
+  workflow_dispatch: {}
+
+concurrency:
+  group: images-${{ github.ref }}
+  cancel-in-progress: true
+
+env:
+  REGISTRY: gitea.whitlocktech.com
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out the merged commit
+        uses: actions/checkout@v4
+
+      - name: Derive image refs (registry owner must be lowercase for Docker)
+        run: |
+          set -euo pipefail
+          OWNER="$(echo "${{ github.repository_owner }}" | tr '[:upper:]' '[:lower:]')"
+          SHORT_SHA="${GITHUB_SHA:0:7}"
+          echo "APP_IMAGE=${REGISTRY}/${OWNER}/website-app" >> "$GITHUB_ENV"
+          echo "BOT_IMAGE=${REGISTRY}/${OWNER}/website-bot" >> "$GITHUB_ENV"
+          echo "TAG=sha-${SHORT_SHA}" >> "$GITHUB_ENV"
+
+      - name: Verify the Docker daemon is reachable
+        # Fails fast with a clear message if the host socket isn't mounted into
+        # the job container (the one hard runner prerequisite).
+        run: |
+          set -euo pipefail
+          if ! docker info >/dev/null 2>&1; then
+            echo "::error::Docker daemon not reachable. Mount /var/run/docker.sock into the runner's job containers."
+            exit 1
+          fi
+          echo "Docker daemon OK"
+
+      - name: Log in to the Gitea container registry
+        run: |
+          set -euo pipefail
+          echo "${{ secrets.REGISTRY_TOKEN }}" \
+            | docker login "${REGISTRY}" -u "${{ secrets.REGISTRY_USER }}" --password-stdin
+
+      - name: Build & push the app image (server + client)
+        run: |
+          set -euo pipefail
+          docker build -f Dockerfile \
+            -t "${APP_IMAGE}:latest" \
+            -t "${APP_IMAGE}:${TAG}" \
+            .
+          docker push "${APP_IMAGE}:latest"
+          docker push "${APP_IMAGE}:${TAG}"
+
+      - name: Build & push the bot image
+        run: |
+          set -euo pipefail
+          docker build -f bot/Dockerfile \
+            -t "${BOT_IMAGE}:latest" \
+            -t "${BOT_IMAGE}:${TAG}" \
+            .
+          docker push "${BOT_IMAGE}:latest"
+          docker push "${BOT_IMAGE}:${TAG}"
+
+      - name: Log out (clear cached credentials from the runner)
+        if: always()
+        run: docker logout "${REGISTRY}" || true