Replace Alpine container with musl-tools on Ubuntu for portable builds

Alpine containers on ARM64 runners break GitHub Actions JS-based
actions (checkout, upload-artifact). Use musl-gcc on Ubuntu instead.

Author: DeusData

.github/workflows/_build.yml

@@ -136,6 +136,8 @@ jobs:
           path: "*.zip"
 
   build-linux-portable:
+    # Static musl builds — uses musl-tools on Ubuntu (not Alpine containers,
+    # which break on ARM64 due to GitHub Actions JS action limitation).
     strategy:
       fail-fast: false
       matrix:
@@ -145,17 +147,21 @@ jobs:
           - arch: arm64
             runner: ubuntu-24.04-arm
     runs-on: ${{ matrix.runner }}
-    container:
-      image: alpine:3.21
     timeout-minutes: 15
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
 
       - name: Install musl build deps
-        run: apk add --no-cache build-base linux-headers zlib-dev zlib-static nodejs npm bash
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y musl-tools zlib1g-dev nodejs npm
+
+      - uses: actions/setup-node@53b83947a5a98c8d113130e565377fae1a50d02f # v6.3.0
+        with:
+          node-version: "22"
 
-      - name: Build standard binary (static)
-        run: scripts/build.sh ${{ inputs.version && format('--version {0}', inputs.version) || '' }} CC=gcc CXX=g++ STATIC=1
+      - name: Build standard binary (static musl)
+        run: scripts/build.sh ${{ inputs.version && format('--version {0}', inputs.version) || '' }} CC=musl-gcc CXX=g++ STATIC=1
 
       - name: Verify static linking
         run: file build/c/codebase-memory-mcp | grep -q "statically linked"
@@ -166,8 +172,8 @@ jobs:
           tar -czf codebase-memory-mcp-linux-${{ matrix.arch }}-portable.tar.gz \
             -C build/c codebase-memory-mcp LICENSE install.sh
 
-      - name: Build UI binary (static)
-        run: scripts/build.sh --with-ui ${{ inputs.version && format('--version {0}', inputs.version) || '' }} CC=gcc CXX=g++ STATIC=1
+      - name: Build UI binary (static musl)
+        run: scripts/build.sh --with-ui ${{ inputs.version && format('--version {0}', inputs.version) || '' }} CC=musl-gcc CXX=g++ STATIC=1
 
       - name: Archive UI binary
         run: |