ci: migrate to Gitea Actions for docker build

Origin moved from GitHub to Gitea. release-please-action and ghcr.io are
GitHub-specific and don't work on Gitea Actions, so the release-please
flow is dropped in favor of manual tag-trigger docker builds.

- Add .gitea/workflows/docker-build.yml: builds and pushes to
  gitea.shcizo.se/shcizo/pdga-rating on tag push (v*)
- Remove release-please-config.json and .release-please-manifest.json
- Neutralize .github/workflows/release-please.yml to workflow_dispatch
  (kept as reference; can't be deleted via tooling under .github/)

.gitea/workflows/docker-build.yml

@@ -0,0 +1,37 @@
+name: Docker Build
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: docker/login-action@v3
+        with:
+          registry: gitea.shcizo.se
+          username: ${{ gitea.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - uses: docker/metadata-action@v5
+        id: meta
+        with:
+          images: gitea.shcizo.se/shcizo/pdga-rating
+          tags: |
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=raw,value=latest
+
+      - uses: docker/build-push-action@v6
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}

.github/workflows/release-please.yml

@@ -1,52 +1,13 @@
-name: Release Please
+# Deprecated: replaced by .gitea/workflows/docker-build.yml (tag-trigger).
+# Origin moved from GitHub to Gitea; release-please-action and ghcr.io are
+# GitHub-only and don't run on Gitea Actions. Trigger changed to manual-only
+# so neither GitHub nor Gitea Actions will auto-run this file.
+name: Release Please (deprecated)
 on:
-  push:
+  workflow_dispatch:
-    branches: [main]
-
-permissions:
-  contents: write
-  pull-requests: write
 
 jobs:
-  release-please:
+  noop:
     runs-on: ubuntu-latest
-    outputs:
-      release_created: ${{ steps.release.outputs.release_created }}
-      tag_name: ${{ steps.release.outputs.tag_name }}
     steps:
-      - uses: googleapis/release-please-action@v4
+      - run: echo "Deprecated. See .gitea/workflows/docker-build.yml"
-        id: release
-        with:
-          release-type: node
-
-  docker:
-    needs: release-please
-    if: ${{ needs.release-please.outputs.release_created }}
-    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: ${{ secrets.GITHUB_TOKEN }}
-
-      - uses: docker/metadata-action@v5
-        id: meta
-        with:
-          images: ghcr.io/${{ github.repository }}
-          tags: |
-            type=semver,pattern={{version}},value=${{ needs.release-please.outputs.tag_name }}
-            type=semver,pattern={{major}}.{{minor}},value=${{ needs.release-please.outputs.tag_name }}
-            type=raw,value=latest
-
-      - uses: docker/build-push-action@v6
-        with:
-          context: .
-          push: true
-          tags: ${{ steps.meta.outputs.tags }}
-          labels: ${{ steps.meta.outputs.labels }}

.release-please-manifest.json

@@ -1,3 +0,0 @@
-{
-  ".": "1.2.0"
-}

release-please-config.json

@@ -1,13 +0,0 @@
-{
-  "packages": {
-    ".": {
-      "release-type": "node",
-      "changelog-sections": [
-        { "type": "feat", "section": "Features" },
-        { "type": "fix", "section": "Bug Fixes" },
-        { "type": "chore", "section": "Miscellaneous" },
-        { "type": "refactor", "section": "Code Refactoring" }
-      ]
-    }
-  }
-}