fix: always re-register runner to keep labels in sync

Init container previously skipped registration if .runner existed on PVC.
Changing labels in values.yaml had no effect until PVC was manually deleted.

Now: rm -f .runner + register on every pod start. Labels always match
values.yaml. No manual intervention needed after merge.

k8s/infra/forgejo-runner/templates/deployment.yaml

@@ -34,7 +34,11 @@ spec:
           command: ["sh", "-c"]
           args:
             - |
-              test -f /data/.runner || forgejo-runner register --no-interactive \
+              # Always re-register to keep labels in sync with values.yaml.
+              # Without this, changing a runner label requires manually deleting
+              # the PVC or .runner file — not GitOps-friendly.
+              rm -f /data/.runner
+              forgejo-runner register --no-interactive \
                 --instance {{ .Values.runner.forgejoUrl }} \
                 --token $(RUNNER_TOKEN) \
                 --name {{ .Values.runner.name }} \