ci: mount windy-pro's read-only build inputs into dind; allow exactly that path for jobs

Non-secret inputs git-ignored in windy-pro (models, linux-x64 portable
bundle, enter-monitor build) that build-desktop needs. Mounted :ro into
dind; valid_volumes allows only /ci-inputs/windy-pro; refresh-ci-inputs.sh
copies them from the frozen release clone (read-only on the source).
Invariant I-5 narrowed, not dropped: exactly that one path, read-only in
dind, no other service mounts it, still no docker socket (proven to fail
on :rw). Orchestrator-approved (option a). Applied in an idle window.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

deploy/runner/config.yaml

@@ -54,6 +54,9 @@ container:
   privileged: false
   options:
   workdir_parent: /workspace
-  valid_volumes: []      # a job cannot bind-mount anything from the daemon host
+  # A job may bind-mount exactly ONE daemon path: the read-only windy-pro build
+  # inputs (mounted :ro into dind itself). Per-runner, not per-repo (act_runner
+  # limit): any windyadmin repo could mount it; it is non-secret and read-only.
+  valid_volumes: ["/ci-inputs/windy-pro"]
   docker_host: "-"       # do NOT expose the runner's own docker socket to jobs
   force_pull: false