fix(renovate): run renovate image directly instead of docker-wrapping action

renovatebot/github-action is a Node wrapper that shells out to
`docker run ghcr.io/renovatebot/renovate`, requiring a Docker CLI + socket
inside the job. The Gitea runner executes the job in a plain node:22 container
with neither, so it died on "Unable to locate executable file: docker".

Run the renovate image as the job container and invoke `renovate` directly —
drops the docker-in-docker requirement. Full tag pinned; Renovate's
github-actions manager keeps container.image bumped.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitea/workflows/renovate.yml

@@ -16,9 +16,18 @@ concurrency:
 jobs:
   renovate:
     runs-on: docker
+    # Run the Renovate image *as* the job container and invoke the `renovate`
+    # binary directly. The renovatebot/github-action wrapper is a thin Node
+    # action that shells out to `docker run …` — it needs a Docker CLI + socket
+    # inside the job, which the Gitea runner's plain node container has not, so
+    # it died on "Unable to locate executable file: docker". Running the image
+    # directly drops the docker-in-docker requirement entirely.
+    # Full tag pinned; Renovate's github-actions manager keeps it bumped.
+    container:
+      image: ghcr.io/renovatebot/renovate:43.232.0
     steps:
       - name: Run Renovate
-        uses: renovatebot/github-action@v40
+        run: renovate
         env:
           # Self-hosted Gitea, not github.com.
           RENOVATE_PLATFORM: gitea