ci: drop the backend e2e step from the dev image pipeline

AGENTS.md

@@ -80,7 +80,7 @@ First run of the Backend prints a claim code in its log; the admin UI asks for i
 Triggers, tags and image paths are defined in `.woodpecker/*.yml` and [`docs/ops/deployment.md`](docs/ops/deployment.md). Verify them there before changing or describing them. The rules below are the stable contract.
 
 - Every push to `main` runs the fast Backend tests and the web build. Both must pass before images are published.
-- A commit message containing `[CI]` builds and pushes development images. `[CI SKIP]` skips the pipeline; `[SKIP TESTS]` skips only the Backend tests. Slow end-to-end tests run after image publication and do not block it.
+- A commit message containing `[CI]` builds and pushes development images. `[CI SKIP]` skips the pipeline; `[SKIP TESTS]` skips only the Backend tests. Slow end-to-end tests run only for pushes without `[CI]` and for pull requests.
 - A tag `vMAJOR.MINOR.PATCH` runs the full cross-platform release pipeline. No version-bump commit is needed.
 - Versions are produced by `ci/version.sh`. The `<Version>` in `backend/Directory.Build.props` and the `version` in `web` `package.json` files are placeholders (`0.0.0-dev`) and must not be edited.
 - Linux Agent builds use `ci/build-linux-agent.sh` for glibc on amd64/arm64 and musl on arm64 in both dev and tag workflows. OCI and OpenWrt installers reuse these native outputs; Windows runners build only Windows/macOS.