port pi-devbox v1.1.4–v1.1.6 hardening; bump opencode 1.17.7→1.17.8

Functional (not verbatim) port of the build-provenance, CI-hardening, SSH
and shell fixes from the sibling pi-devbox repo, adapted to opencode-devbox's
companions and two-variant (base/omos) shape. Defaults unchanged → canonical
CI build stays byte-identical apart from the opencode bump and the
(cache-free) provenance layer.

Fixed:
- SSH read-only ~/.ssh ControlPath: setup-lan-access.sh now renders the
  writable ~/.ssh-local/config sidecar (ControlPath redirect + Include) on
  EVERY host OS instead of exit 0-ing on native Linux; jump-specific blocks
  gated behind new NEED_JUMP flag. dssh/dscp + ControlMaster now survive a
  read-only ~/.ssh on native-Linux hosts. (pi-devbox v1.1.5)
- bash history loss in nested/tmux shells: DEVBOX_HIST_SET no longer exported
  so each shell re-installs its own history -a flush. (pi-devbox v1.1.4)

Added:
- build provenance: OCI labels + /etc/opencode-devbox/build-manifest.json
  written from ground truth (opencode --version, installed omos version,
  /opt/mempalace-toolkit HEAD); wired into build-variant-* and smoke-* jobs;
  smoke-test.sh asserts manifest + label. (pi-devbox v1.1.6)
- scripts/check-base-hash.sh CI guard: fails if a Dockerfile.base ARG *_REF
  is not folded into the base_tag hash. (pi-devbox v1.1.6)
- overridable MEMPALACE_TOOLKIT_REPO build-arg in Dockerfile.base. (v1.1.6)

Changed:
- resolve-versions: fail-loud validation (SHA / semver) that aborts the
  release instead of silently falling back to floating main; adds shell: bash
  (set -o pipefail is illegal under the runner default dash). (pi-devbox v1.1.6)

Bumped:
- opencode-ai 1.17.7 → 1.17.8 (current npm latest stable).

Deferred (needs a decision): opencode.json merge-on-recreate — see CHANGELOG.

entrypoint-user.sh

@@ -12,12 +12,16 @@ set -euo pipefail
 mkdir -p /tmp/sshcm
 chmod 700 /tmp/sshcm
 
-# ── LAN access: generic host-OS-agnostic reachability helper ────────
-# On VM-backed hosts (macOS OrbStack / Docker Desktop) the container can't
-# reach the host's directly-attached LAN peers by default; this generates a
-# writable ~/.ssh-local/config that uses the host as an SSH jump. On native
-# Linux (LAN reachable directly) it is a no-op. Controlled by DEVBOX_LAN_ACCESS
-# (auto|jump|off) + HOST_SSH_USER. Always non-fatal. See the script header.
+# ── LAN access + writable SSH sidecar: host-OS-agnostic helper ──────
+# Generates the writable ~/.ssh-local/config on EVERY host OS: a `Host *`
+# ControlPath redirect into ~/.ssh-local/cm (so `ssh -F` / dssh / dscp work
+# even when ~/.ssh is bind-mounted read-only) plus `Include ~/.ssh/config`. On
+# VM-backed hosts (macOS OrbStack / Docker Desktop) it ALSO adds an
+# SSH-jump-via-host block so the container can reach the host's
+# directly-attached LAN peers; on native Linux (LAN reachable directly) the
+# jump block is omitted but the sidecar is still rendered. Controlled by
+# DEVBOX_LAN_ACCESS (auto|jump|off) + HOST_SSH_USER. Always non-fatal. See the
+# script header.
 if [ -r /usr/local/lib/opencode-devbox/setup-lan-access.sh ]; then
   bash /usr/local/lib/opencode-devbox/setup-lan-access.sh || true
 fi