chore(renovate): move config under renovate/ and validate it in CI

The config lived in renovate.json at the repo root while everything else
Renovate-related sat under renovate/, and renovate/config.js was a second,
unused source of truth. Both are gone: renovate/renovate.json is now the
only config file.

Because the CronJob in the cluster cannot read the repository, its
ConfigMap carries an inlined copy of the config. That copy is generated,
and sync-renovate-configmap.sh --check now fails the build when it drifts
from the source file.

The workflows also stop carrying a copy of the renovate/renovate image
tag. They read it from renovate/k8s/cronjob.yaml, so the version validated
in CI is the version that actually runs in the cluster.

ci.yaml validates the config with renovate-config-validator, checks the
generated ConfigMap, and kubeconforms the CronJob's own manifests.

.gitea/workflows/renovate-run.yaml

@@ -28,18 +28,36 @@ concurrency:
 jobs:
   run-renovate:
     runs-on: [self-hosted, linux, arch, homelab]
+    timeout-minutes: 60
     steps:
       - name: Checkout repository
         uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
 
+      # renovate/k8s/cronjob.yaml is the single source of truth for the image tag.
+      # Reading it here means this workflow validates and runs the exact version
+      # that is deployed, instead of a copy that silently goes stale.
+      - name: Resolve the deployed Renovate image
+        id: image
+        shell: bash
+        run: |
+          set -euo pipefail
+          image="$(sed -n 's|.*image:[[:space:]]*\(renovate/renovate:[^[:space:]]*\).*|\1|p' \
+            renovate/k8s/cronjob.yaml | head -1)"
+          if [ -z "$image" ]; then
+            echo "::error::no renovate/renovate image found in renovate/k8s/cronjob.yaml"
+            exit 1
+          fi
+          echo "using $image"
+          echo "image=$image" >> "$GITHUB_OUTPUT"
+
       - name: Validate Renovate config
         shell: bash
         run: |
           set -euo pipefail
           docker run --rm \
-            -v "$PWD/renovate/config.js:/opt/renovate/config.js:ro" \
-            -e RENOVATE_CONFIG_FILE=/opt/renovate/config.js \
-            renovate/renovate:44.103.0 \
+            -v "$PWD/renovate/renovate.json:/opt/renovate/renovate.json:ro" \
+            -e RENOVATE_CONFIG_FILE=/opt/renovate/renovate.json \
+            "${{ steps.image.outputs.image }}" \
             renovate-config-validator
 
       - name: Run Renovate
@@ -56,14 +74,14 @@ jobs:
           : "${RENOVATE_TOKEN:?missing RENOVATE_TOKEN secret — add a renovate-bot PAT in repo/org Actions secrets}"
 
           docker run --rm \
-            -v "$PWD/renovate/config.js:/opt/renovate/config.js:ro" \
+            -v "$PWD/renovate/renovate.json:/opt/renovate/renovate.json:ro" \
             -e RENOVATE_PLATFORM=gitea \
             -e RENOVATE_ENDPOINT=https://gitea.forust.xyz/api/v1 \
             -e RENOVATE_TOKEN="$RENOVATE_TOKEN" \
             -e RENOVATE_GITHUB_COM_TOKEN="${RENOVATE_GITHUB_COM_TOKEN:-}" \
             -e RENOVATE_REPOSITORIES="${RENOVATE_REPOSITORIES:-forust/homelab}" \
             -e RENOVATE_DRY_RUN="${RENOVATE_DRY_RUN:-}" \
-            -e RENOVATE_CONFIG_FILE=/opt/renovate/config.js \
+            -e RENOVATE_CONFIG_FILE=/opt/renovate/renovate.json \
             -e RENOVATE_BASE_DIR=/tmp/renovate \
             -e LOG_LEVEL="${LOG_LEVEL:-info}" \
-            renovate/renovate:44.103.0
+            "${{ steps.image.outputs.image }}"