ci: add Gitea workflow to build and push image on main

Same auto-build setup as CncApi and LaserQuote.Web so all forge
services publish to the Gitea registry on push instead of the
manual docker save/load flow.

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

.gitea/workflows/build-pepapi.yml

@@ -0,0 +1,28 @@
+name: Build PepApi image
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - "PepApi.Core/**"
+      - "PepLib.Core/**"
+      - "Dockerfile"
+      - ".gitea/workflows/build-pepapi.yml"
+  workflow_dispatch: {}
+
+jobs:
+  build-and-push:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Log in to Gitea container registry
+        run: echo "${{ secrets.REGISTRY_TOKEN }}" | docker login git.thecozycat.net -u "${{ gitea.actor }}" --password-stdin
+
+      - name: Build image
+        run: docker build -t git.thecozycat.net/${{ gitea.repository_owner }}/pepapi:latest -t git.thecozycat.net/${{ gitea.repository_owner }}/pepapi:${{ gitea.sha }} .
+
+      - name: Push image
+        run: |
+          docker push git.thecozycat.net/${{ gitea.repository_owner }}/pepapi:latest
+          docker push git.thecozycat.net/${{ gitea.repository_owner }}/pepapi:${{ gitea.sha }}