feat: host-agnostic LAN access (base) + fork/recall in pi variants

Item A — LAN access (base image):
- New rootfs/usr/local/lib/opencode-devbox/setup-lan-access.sh, invoked
  non-fatally from entrypoint-user.sh. On VM-backed hosts (macOS OrbStack /
  Docker Desktop, detected via host.docker.internal) it generates a writable
  ~/.ssh-local/config that uses the host as an SSH jump to reach LAN peers;
  no-op on native Linux. Ships the mechanism (generic 'host' jump alias),
  not policy (targets stay in the user's bind-mounted ~/.ssh/config).
- New env knobs: DEVBOX_LAN_ACCESS (auto|jump|off), HOST_SSH_USER,
  DEVBOX_HOST_ALIAS. dssh/dscp aliases in .bash_aliases (guarded).

Item B — pi-fork (fork) + pi-observational-memory (recall) in pi variants:
- Dockerfile.variant clones both elpapi42 repos to /opt and runs npm install
  there at build time (local-path 'pi install' does not npm-install, so deps
  must be present to load). New args PI_FORK_REPO/REF, PI_OBSMEM_REPO/REF.
- entrypoint-user.sh registers them at runtime via 'pi install /opt/<pkg>'
  (instant, in-place, idempotent; tools bind on next pi start).
- CI resolve-versions resolves each repo's master HEAD to a commit SHA and
  passes PI_FORK_REF/PI_OBSMEM_REF — same cache-hit guard as PI_VERSION.
- smoke-test asserts /opt clones + node_modules + settings.json registration;
  size thresholds bumped (with-pi 2700->2900, omos-with-pi 3700->3900).

Versions unchanged (opencode 1.15.13, pi 0.78.0 — both still latest).
Docs: README LAN section + env table, .env.example, AGENTS.md, CHANGELOG.
Plan recorded in docs/plan-lan-access-and-pi-extensions.md.

.gitea/workflows/docker-publish-split.yml

@@ -122,6 +122,8 @@ jobs:
     outputs:
       pi_version: ${{ steps.resolve.outputs.pi_version }}
       omos_version: ${{ steps.resolve.outputs.omos_version }}
+      fork_ref: ${{ steps.resolve.outputs.fork_ref }}
+      obsmem_ref: ${{ steps.resolve.outputs.obsmem_ref }}
     steps:
       - name: Resolve pi + omos versions from npm registry
         id: resolve
@@ -136,7 +138,23 @@ jobs:
           OMOS_VERSION=$(curl -sf "https://registry.npmjs.org/oh-my-opencode-slim/latest" | jq -r '.version')
           echo "pi_version=${PI_VERSION}"     >> "$GITHUB_OUTPUT"
           echo "omos_version=${OMOS_VERSION}" >> "$GITHUB_OUTPUT"
+          # Resolve the pi-fork / pi-observational-memory git refs (default
+          # branch master) to concrete commit SHAs so the build-arg string
+          # changes whenever upstream moves — defeating the same registry-
+          # buildcache cache-hit footgun that PI_VERSION/OMOS_VERSION guard
+          # against. The Accept: application/vnd.github.sha media type returns
+          # the bare SHA. Falls back to the branch name if the API is
+          # unreachable/rate-limited (still functional, just cache-stale-prone).
+          FORK_REF=$(curl -sf -H "Accept: application/vnd.github.sha" \
+            "https://api.github.com/repos/elpapi42/pi-fork/commits/master" || echo "master")
+          OBSMEM_REF=$(curl -sf -H "Accept: application/vnd.github.sha" \
+            "https://api.github.com/repos/elpapi42/pi-observational-memory/commits/master" || echo "master")
+          [ -n "$FORK_REF" ]   || FORK_REF=master
+          [ -n "$OBSMEM_REF" ] || OBSMEM_REF=master
+          echo "fork_ref=${FORK_REF}"     >> "$GITHUB_OUTPUT"
+          echo "obsmem_ref=${OBSMEM_REF}" >> "$GITHUB_OUTPUT"
           echo "Resolved PI_VERSION=${PI_VERSION}, OMOS_VERSION=${OMOS_VERSION}"
+          echo "Resolved PI_FORK_REF=${FORK_REF}, PI_OBSMEM_REF=${OBSMEM_REF}"
 
   # ── Phase 2: build & push base (multi-arch), only when needed ──────
   build-base:
@@ -359,6 +377,8 @@ jobs:
             INSTALL_OMOS=false
             INSTALL_PI=true
             PI_VERSION=${{ needs.resolve-versions.outputs.pi_version }}
+            PI_FORK_REF=${{ needs.resolve-versions.outputs.fork_ref }}
+            PI_OBSMEM_REF=${{ needs.resolve-versions.outputs.obsmem_ref }}
       - env:
           EXPECTED_PI_VERSION: ${{ needs.resolve-versions.outputs.pi_version }}
         run: bash scripts/smoke-test.sh opencode-devbox:smoke-with-pi --variant with-pi
@@ -405,6 +425,8 @@ jobs:
             INSTALL_PI=true
             PI_VERSION=${{ needs.resolve-versions.outputs.pi_version }}
             OMOS_VERSION=${{ needs.resolve-versions.outputs.omos_version }}
+            PI_FORK_REF=${{ needs.resolve-versions.outputs.fork_ref }}
+            PI_OBSMEM_REF=${{ needs.resolve-versions.outputs.obsmem_ref }}
       - env:
           EXPECTED_PI_VERSION: ${{ needs.resolve-versions.outputs.pi_version }}
           EXPECTED_OMOS_VERSION: ${{ needs.resolve-versions.outputs.omos_version }}
@@ -594,6 +616,8 @@ jobs:
           TAGS: ${{ steps.tags.outputs.tags }}
           BASE_IMAGE_FULL: ${{ env.IMAGE }}:${{ needs.base-decide.outputs.base_tag }}
           PI_VERSION: ${{ needs.resolve-versions.outputs.pi_version }}
+          FORK_REF: ${{ needs.resolve-versions.outputs.fork_ref }}
+          OBSMEM_REF: ${{ needs.resolve-versions.outputs.obsmem_ref }}
         run: |
           set -euo pipefail
           TAG_FLAGS=()
@@ -610,6 +634,8 @@ jobs:
                 --build-arg "INSTALL_OMOS=false" \
                 --build-arg "INSTALL_PI=true" \
                 --build-arg "PI_VERSION=${PI_VERSION}" \
+                --build-arg "PI_FORK_REF=${FORK_REF}" \
+                --build-arg "PI_OBSMEM_REF=${OBSMEM_REF}" \
                 "${TAG_FLAGS[@]}" \
                 .; then
               echo "==> Attempt ${attempt} succeeded"
@@ -666,6 +692,8 @@ jobs:
           BASE_IMAGE_FULL: ${{ env.IMAGE }}:${{ needs.base-decide.outputs.base_tag }}
           PI_VERSION: ${{ needs.resolve-versions.outputs.pi_version }}
           OMOS_VERSION: ${{ needs.resolve-versions.outputs.omos_version }}
+          FORK_REF: ${{ needs.resolve-versions.outputs.fork_ref }}
+          OBSMEM_REF: ${{ needs.resolve-versions.outputs.obsmem_ref }}
         run: |
           set -euo pipefail
           TAG_FLAGS=()
@@ -683,6 +711,8 @@ jobs:
                 --build-arg "INSTALL_PI=true" \
                 --build-arg "PI_VERSION=${PI_VERSION}" \
                 --build-arg "OMOS_VERSION=${OMOS_VERSION}" \
+                --build-arg "PI_FORK_REF=${FORK_REF}" \
+                --build-arg "PI_OBSMEM_REF=${OBSMEM_REF}" \
                 "${TAG_FLAGS[@]}" \
                 .; then
               echo "==> Attempt ${attempt} succeeded"