ci: use pre-built elc-linux-amd64 from El SDK v1.2.1 release

Replaces the three-step apt install + GCS cache probe + gcc build sequence
with a single curl download of the pre-built binary. Eliminates build-time
C toolchain dependency and shaves ~2-3 minutes off every full build.

.gitea/workflows/deploy.yaml

@@ -95,49 +95,15 @@ jobs:
       - name: Configure docker auth for Artifact Registry
         run: gcloud auth configure-docker us-central1-docker.pkg.dev --quiet
 
-      - name: Install C build deps for elc
+      - name: Get elc (pre-built linux/amd64 from El SDK release)
         if: steps.changetype.outputs.asset_only != 'true'
-        run: |
-          sudo apt-get update -qq
-          sudo apt-get install -y --no-install-recommends build-essential libcurl4-openssl-dev libssl-dev
-
-      - name: Restore elc binary from GCS cache
-        if: steps.changetype.outputs.asset_only != 'true'
-        id: elc-cache
         run: |
           set -euo pipefail
-          # Cache key = SHA256 of both source files that produce elc
-          ELC_SRC_HASH=$(cat "$EL_HOME/dist/platform/elc.c" "$EL_HOME/el-compiler/runtime/el_runtime.c" | sha256sum | cut -c1-16)
-          CACHE_OBJ="gs://neuron-ci-cache/elc/linux-amd64/${ELC_SRC_HASH}/elc"
-          echo "elc_cache_key=${ELC_SRC_HASH}" >> "$GITHUB_OUTPUT"
-          echo "elc_cache_obj=${CACHE_OBJ}" >> "$GITHUB_OUTPUT"
-          if gsutil -q stat "$CACHE_OBJ" 2>/dev/null; then
-            echo "Cache hit: ${CACHE_OBJ}"
-            gsutil cp "$CACHE_OBJ" "$EL_HOME/dist/platform/elc"
-            chmod +x "$EL_HOME/dist/platform/elc"
-            echo "cache_hit=true" >> "$GITHUB_OUTPUT"
-          else
-            echo "Cache miss for key ${ELC_SRC_HASH}"
-            echo "cache_hit=false" >> "$GITHUB_OUTPUT"
-          fi
-
-      - name: Build elc (cache miss only)
-        if: steps.changetype.outputs.asset_only != 'true' && steps.elc-cache.outputs.cache_hit != 'true'
-        run: |
-          set -euo pipefail
-          # The committed dist/platform/elc is arm64 from Will's mac. We
-          # rebuild from dist/platform/elc.c (the canonical C source) so
-          # the binary matches the runner's linux/amd64.
-          cd "$EL_HOME"
-          cc -O2 -o dist/platform/elc \
-            dist/platform/elc.c \
-            el-compiler/runtime/el_runtime.c \
-            -I el-compiler/runtime \
-            -lcurl -lpthread -ldl -lm -lssl -lcrypto
-          file dist/platform/elc
-          ls -la dist/platform/elc
-          # Upload to GCS cache for future runs
-          gsutil cp dist/platform/elc "${{ steps.elc-cache.outputs.elc_cache_obj }}" || true
+          curl -fL -o "$EL_HOME/dist/platform/elc" \
+            https://git.neuralplatform.ai/neuron-technologies/el/releases/download/v1.2.1/elc-linux-amd64
+          chmod +x "$EL_HOME/dist/platform/elc"
+          file "$EL_HOME/dist/platform/elc"
+          ls -la "$EL_HOME/dist/platform/elc"
 
       - name: Compute image tag
         id: tag