feat: Woodpecker-Plugin deploy für oumta-deploy

Schreibt dev- und beta-Images mit Digest nach tanztee/oumta-deploy über
dessen ci/deploy-image.sh. Gebaut per .woodpecker/plugins.yaml, Release
über Tag deploy-vX.Y.Z.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -117,3 +117,54 @@ jobs:
           kubeconfig: ${{ secrets.KUBECONFIG }}
           registry: ${{ secrets.REGISTRY }}
 ```
+
+## Woodpecker plugins
+
+Plugins are Docker images built from `woodpecker/<name>/` by `.woodpecker/plugins.yaml`. A tag `<name>-vX.Y.Z` publishes `git.uesome.de/actions/ci-cd/<name>:vX.Y.Z`; pipelines pin that version.
+
+### deploy
+
+Writes a pushed dev or beta image with its digest to `tanztee/oumta-deploy` (D16 there). `ci/deploy-image.sh` in oumta-deploy decides the environment from the tag: `-dev.` goes to dev, `-beta.` to beta, anything else is skipped (prod only via PR).
+
+Settings:
+
+- `var` (required): variable in `envs/<env>/images.env`, e.g. `AUTH_IMAGE`. `{major}` is replaced by the major of the tag (`APP_V{major}_IMAGE` -> `APP_V2_IMAGE`).
+- `deploy_token` (required): token of `oumta-ci`, write access to oumta-deploy only. Limit the secret to this image and the events `tag` and `manual`.
+- `registry_username`, `registry_password`: read access to the registry for the digest
+- `envs`: fixed environments instead of the tag rule, e.g. `dev beta` (oumta-keyklo)
+- `tag`: default `CI_COMMIT_TAG`
+- `registry`: default `git.uesome.de`
+- `image`: default `<registry>/<CI_REPO>`
+- `deploy_user`: default `oumta-ci`
+- `deploy_repo`: default `https://git.uesome.de/tanztee/oumta-deploy.git`
+
+Example:
+
+```yaml
+when:
+  event: tag
+  ref: refs/tags/v*
+
+steps:
+  - name: build
+    image: woodpeckerci/plugin-docker-buildx:6.1.2
+    settings:
+      registry: git.uesome.de
+      repo: git.uesome.de/tanztee/oumta-auth
+      tags: ${CI_COMMIT_TAG}
+      username:
+        from_secret: registry_username
+      password:
+        from_secret: registry_password
+
+  - name: deploy
+    image: git.uesome.de/actions/ci-cd/deploy:v1.0.0
+    settings:
+      var: AUTH_IMAGE
+      registry_username:
+        from_secret: registry_username
+      registry_password:
+        from_secret: registry_password
+      deploy_token:
+        from_secret: oumta_deploy_token
+```