ci: pin soul build to vendored release runtime v1.0.0-20260501

The soul build downloaded el-runtime-c 'latest' from Artifact Registry. The
merged ship-soul calls engram_prune_telemetry, which the latest published
runtime no longer defines, so an unpinned build fails to link — the failure
mode that let a broken/handlerless soul reach prod.

Vendor the release runtime v1.0.0-20260501 (el_runtime.c/.h) into the repo and
compile the soul against it. This is the exact runtime the merged soul was
verified against (verify-soul-contract GATE PASS, genesis boot survives, full
safety-contact response), making the build reproducible and independent of a
moving AR 'latest'.

The verify-soul-contract.sh HARD-BLOCK gate already runs before Publish (from
the CI-hardening arc on main), so a destructive or stale soul can never
publish/deploy again.

.gitea/workflows/ci.yaml

@@ -39,7 +39,7 @@ jobs:
             > /etc/apt/sources.list.d/google-cloud-sdk.list
           apt-get update -qq && apt-get install -y google-cloud-cli
 
-      - name: Download El runtime from Artifact Registry
+      - name: Authenticate to GCP + stage PINNED El runtime
         env:
           GCP_SA_KEY: ${{ secrets.GCP_SA_KEY }}
         run: |
@@ -47,41 +47,21 @@ jobs:
           gcloud auth activate-service-account --key-file=/tmp/gcp-key.json
           gcloud config set project neuron-785695
 
+          # PINNED RUNTIME — do NOT pull "latest" from Artifact Registry.
+          # The ship-soul calls engram_prune_telemetry (awareness.el sync/heartbeat
+          # self-review). The latest published el-runtime-c no longer defines that
+          # symbol, so an unpinned build fails to LINK — which is exactly how a
+          # broken/handlerless soul reached prod before. Compile against the
+          # vendored release runtime v1.0.0-20260501: the exact runtime the merged
+          # ship-soul was verified against (verify-soul-contract GATE PASS +
+          # genesis boot survives + full safety-contact response). It is committed
+          # under vendor/ so the soul build is fully reproducible and never depends
+          # on a moving AR "latest".
           rm -rf /opt/el/runtime
           mkdir -p /opt/el/runtime
-
-          # Get latest version of each runtime package (elc/elb not needed — we compile
-          # dist/soul.c directly; running elb on Linux OOM-kills the runner, and we
-          # always use the repo's pre-built soul.c anyway).
-          get_latest() {
-            gcloud artifacts versions list \
-              --repository=foundation-prod \
-              --location=us-central1 \
-              --project=neuron-785695 \
-              --package="$1" \
-              --sort-by="~createTime" \
-              --limit=1 \
-              --format="value(name)" 2>/dev/null | awk -F/ '{print $NF}'
-          }
-
-          RC_VER=$(get_latest el-runtime-c)
-          RH_VER=$(get_latest el-runtime-h)
-
-          echo "Downloading runtime@${RC_VER}"
-
-          gcloud artifacts generic download \
-            --repository=foundation-prod --location=us-central1 --project=neuron-785695 \
-            --package=el-runtime-c --version="${RC_VER}" \
-            --destination=/opt/el/runtime/
-
-          gcloud artifacts generic download \
-            --repository=foundation-prod --location=us-central1 --project=neuron-785695 \
-            --package=el-runtime-h --version="${RH_VER}" \
-            --destination=/opt/el/runtime/
-
-          mv /opt/el/runtime/el_runtime.c* /opt/el/runtime/el_runtime.c 2>/dev/null || true
-          mv /opt/el/runtime/el_runtime.h* /opt/el/runtime/el_runtime.h 2>/dev/null || true
-          echo "El runtime ready: $(ls /opt/el/runtime/)"
+          cp vendor/el-runtime/v1.0.0-20260501/el_runtime.c /opt/el/runtime/el_runtime.c
+          cp vendor/el-runtime/v1.0.0-20260501/el_runtime.h /opt/el/runtime/el_runtime.h
+          echo "El runtime PINNED to v1.0.0-20260501: $(ls /opt/el/runtime/)"
 
       - name: Build neuron soul binary
         run: |