Switch CI from build-stage.sh to elb — no OOM

elb compiles each .el source independently (per-file codegen),
avoiding the exponential memory growth from concatenating all sources
into main-combined.el and feeding it to elc in one shot.

- dev.yaml: replace build-stage.sh with elb build + per-file JS elc
- Dockerfile.stage: COPY dist/neuron-landing (elb binary) directly
  instead of compiling from pre-generated main.c. soul-demo stays as
  cc compilation (small file, no risk).

.gitea/workflows/dev.yaml

@@ -12,7 +12,7 @@ on:
       - 'dist/**'
       - 'runtime/**'
       - 'Dockerfile.stage'
-      - 'build-stage.sh'
+      - 'manifest.el'
       - '.gitea/workflows/dev.yaml'
       - '.gitea/workflows/stage.yaml'
       - '.gitea/workflows/deploy.yaml'
@@ -60,8 +60,38 @@ jobs:
         # idempotent if the files already exist from a prior run.
         run: touch src/index.html src/about.html src/terms.html src/enterprise-terms.html
 
-      - name: Build image (local only — no push)
-        run: ./build-stage.sh "${{ steps.tag.outputs.tag }}"
+      - name: Build El binary (elb)
+        # elb compiles each .el source independently (no combined mega-file),
+        # then links via cc. Output: dist/neuron-landing (linux/amd64 binary).
+        # This avoids the exponential memory growth that hits elc on the
+        # concatenated main-combined.el approach.
+        run: |
+          set -euo pipefail
+          export EL_HOME=/opt/el
+          /opt/el/dist/bin/elb build
+          echo "Binary: $(ls -lh dist/neuron-landing)"
+
+      - name: Compile JS El sources
+        run: |
+          set -euo pipefail
+          ELC=/opt/el/dist/platform/elc
+          mkdir -p dist/js
+          for f in src/js/*.el; do
+            [ -f "$f" ] || continue
+            name=$(basename "$f" .el)
+            "$ELC" --target=js --bundle --minify --obfuscate "$f" > "dist/js/${name}.js"
+            echo "  compiled: $f → dist/js/${name}.js"
+          done
+
+      - name: Build Docker image (local only — no push)
+        run: |
+          set -euo pipefail
+          TAG="${{ steps.tag.outputs.tag }}"
+          docker build \
+            --cache-from us-central1-docker.pkg.dev/neuron-785695/neuron-marketing/marketing:latest \
+            -f Dockerfile.stage \
+            -t "marketing:${TAG}" \
+            .
 
       - name: Local smoke test
         run: |