chore(github-runner): un-park github-runner-sharedpos (Shared.Pos non-root build fixed)

Set replicas back to 1 — the non-root setup-dotnet path issue that drove the
park (replicas: 0 on 2026-05-21) is resolved. Shared.Pos #5 landed a
step-scoped DOTNET_INSTALL_DIR override and today's Shared.Pos publish
succeeded at 01:47 UTC against this runner.

Reconciles git with live K8s state: the github-runner-sharedpos pod is
already Running on rke2-agent2 (4h12m up, 4 restarts). Without this commit,
the next ArgoCD selfHeal would scale it back to 0 and re-stop Shared.Pos
publish flow.

Follow-on: Sprint 30+ Cx-1 fleet-wide pod-env (DOTNET_INSTALL_DIR set on
the Deployment env, not per-workflow) is still queued — once landed, the
per-workflow patch can be backed out.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/github-runner/github-runner.yaml

@@ -233,13 +233,9 @@ metadata:
     app.kubernetes.io/managed-by: argocd
     flowercore.io/created-by: argocd
 spec:
-  # PARKED 2026-05-21: scaled to 0. The Shared.Pos build still fails on the
-  # non-root runner (actions/setup-dotnet -> /usr/share/dotnet denied); a
-  # churning ephemeral runner just retries a doomed build and drives HighCPU
-  # on rke2-agent2. Re-enable (replicas: 1) only as part of the Sprint 30+
-  # Cx-1 Linux-runner-fleet lane, which sets DOTNET_INSTALL_DIR on the runner
-  # pod env fleet-wide. See memory/feedback_flip_sweep_nonroot_runner_workflow_fallout.
-  replicas: 0
+  # UN-PARKED 2026-05-21: Shared.Pos #5 fixed the non-root setup-dotnet path
+  # (DOTNET_INSTALL_DIR step-scoped). Re-enabled to run the now-fixable build.
+  replicas: 1
   selector:
     matchLabels:
       app.kubernetes.io/name: github-runner-sharedpos