Bug: OpenCode fails to start when userspace is backed by JuiceFS (multi-node)

[bayerhazard]

Environment

• Olares 1.12.6, multi-node (control-plane + 1 worker)
• Userspace provisioned with olares-cli install --enable-juicefs
  (JuiceFS FUSE mounted at /olares/rootfs, data backend: local managed-MinIO)
• App: opencode 1.0.18 (this chart), image beclab/opencode:1.18.9.1

Symptom

Pod stays in Init:CrashLoopBackOff. Init container init-overlay
(privileged, runs /opt/olares-bake/lib/init-overlay.sh) exits 255 with:

mount: mounting overlay on /pkg-overlay/merged/usr failed: Not supported

Root cause

• In multi-node mode the userspace (/olares/rootfs/...) is served by
  JuiceFS = a FUSE filesystem (fuse.juicefs).
• This chart places all overlay-dependent paths under the userspace:
  • pkg-overlay upper/work dirs -> {{ .Values.userspace.appData }}/.pkg-overlay
  • dind-storage (dockerd /var/lib/docker) -> {{ .Values.userspace.appData }}
  • the pkg-* merged views -> .../.pkg-overlay/merged/*
    (see templates/opencode.yaml, init-overlay ~L74-92 and volumes ~L395-470)
• OverlayFS cannot use a FUSE filesystem as its upperdir/workdir ->
  kernel returns EOPNOTSUPP ("Not supported"). The same applies to
  docker-dind, which uses the default overlay2 storage driver on the
  JuiceFS-backed docker dir and will fail once init-overlay is bypassed.
• values.yaml exposes no knob (only replicaCount), so the paths cannot
  be relocated at install time.
• Confirmed working when the userspace is a plain hostPath on a real block
  device (single-node / hostpath-userspace). This is a FUSE limitation,
  not an opencode-specific bug.

Impact

Any pkga-based app that uses init-overlay (or dockerd with overlay2) on a
JuiceFS userspace cannot install/start. Multi-node is the default Olares
architecture for multiple nodes, so this blocks opencode there entirely.

Suggested fixes (any of)

1. Preferred: relocate the overlay-dependent volumes (pkg-overlay,
   dind-storage) to a node-local real-disk hostPath (e.g. under the local
   appCache/userData area) instead of the JuiceFS userspace. The overlay
   upper layer is inherently node-local, so this stays compatible with the
   shared JuiceFS userspace for actual user data.
2. Add a values/OlaresManifest knob that selects where pkg-overlay and
   docker storage live.
3. Make init-overlay.sh detect an unsupported (FUSE) upperdir and fall back
   to bind mounts (degraded: no persistent pkg overlay).

Repro

1. Multi-node Olares 1.12.6 installed with --enable-juicefs.
2. Install opencode 1.0.18 from the store.
3. Watch init-overlay CrashLoopBackOff with the mount error above.