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.

scripts/check-base-hash.sh

@@ -0,0 +1,43 @@
+#!/usr/bin/env bash
+# check-base-hash.sh — guard the base-rebuild invariant.
+#
+# Every floating `ARG *_REF` consumed by Dockerfile.base MUST be folded
+# into the base_tag hash in the docker-publish workflow. Otherwise a
+# ref-only change to that dependency does not change the base hash, the
+# Docker Hub probe finds the old base tag, and the base is NOT rebuilt —
+# the dependency fix silently fails to land. This is the v1.1.2-class
+# staleness footgun (then it was mempalace-toolkit; this guard stops the
+# next one before it ships).
+#
+# Runs in CI (base-decide job) and locally:  bash scripts/check-base-hash.sh
+set -euo pipefail
+cd "$(dirname "$0")/.."
+
+WF=".gitea/workflows/docker-publish-split.yml"
+DF="Dockerfile.base"
+
+# Extract the hash-compute block: the `HASH=$( … ) | sha256sum | cut`
+# brace-group in the "Compute base tag" step. This lives in a separate
+# file from the workflow, so scanning $WF here is free of the self-match
+# hazard an inline workflow step would have.
+block=$(awk '/HASH=\$\(/{f=1} f{print} f && /cut -c1-12/{exit}' "$WF")
+if [ -z "$block" ]; then
+  echo "::error::could not locate the HASH=\$( … ) | sha256sum block in $WF"
+  exit 1
+fi
+
+refs=$(grep -oE '^ARG [A-Z0-9_]+_REF' "$DF" | awk '{print $2}' | sort -u)
+fail=0
+for r in $refs; do
+  lc=$(printf '%s' "$r" | tr '[:upper:]' '[:lower:]')
+  if ! printf '%s' "$block" | grep -q "outputs.$lc"; then
+    echo "::error::Dockerfile.base declares '$r' but it is NOT folded into the base_tag hash in $WF."
+    echo "::error::Add  echo \"\${{ needs.resolve-versions.outputs.$lc }}\"  inside the HASH=\$( … ) | sha256sum block, or a $r-only change will silently fail to rebuild the base."
+    fail=1
+  fi
+done
+
+if [ "$fail" = 0 ]; then
+  echo "OK: all Dockerfile.base *_REF args are folded into base_tag (${refs:-none})."
+fi
+exit $fail

scripts/smoke-test.sh

@@ -197,6 +197,34 @@ else
   fi
 fi
 
+echo
+echo "-- Build provenance (manifest + OCI labels) --"
+run "/etc/opencode-devbox/build-manifest.json present" \
+    "test -f /etc/opencode-devbox/build-manifest.json"
+run_expect "manifest records opencode component" \
+    "cat /etc/opencode-devbox/build-manifest.json" '"opencode"'
+run_expect "manifest records opencode_version" \
+    "cat /etc/opencode-devbox/build-manifest.json" '"opencode_version"'
+run_expect "manifest records mempalace-toolkit component" \
+    "cat /etc/opencode-devbox/build-manifest.json" '"mempalace-toolkit"'
+# Every resolved component must be a real value, never the 'unknown'
+# sentinel that rev()/version lookups emit on failure. (oh-my-opencode-slim
+# is JSON null in the base variant — that is expected, not 'unknown'.)
+run "manifest has no unresolved ('unknown') components" \
+    "! grep -q '\"unknown\"' /etc/opencode-devbox/build-manifest.json"
+if [ "$VARIANT" = "omos" ]; then
+  run "manifest omos component is resolved (not null) in omos variant" \
+      "! grep -q '\"oh-my-opencode-slim\": null' /etc/opencode-devbox/build-manifest.json"
+fi
+# OCI labels live in the image config, not the container fs — inspect them
+# from the host docker rather than via `docker run`.
+LBL=$(docker inspect --format '{{ index .Config.Labels "se.jordbo.opencode-devbox.opencode-version" }}' "$IMAGE" 2>/dev/null || true)
+if [ -n "$LBL" ] && [ "$LBL" != "<no value>" ]; then
+  pass "OCI label se.jordbo.opencode-devbox.opencode-version=$LBL"
+else
+  fail "OCI label se.jordbo.opencode-devbox.opencode-version missing or empty"
+fi
+
 echo
 echo "-- Entrypoint behaviour --"