fix(release): build musl via cargo-zigbuild + make release resilient

.github/workflows/release-please.yml

@@ -100,7 +100,10 @@ jobs:
   # npmjs.com pointing at this repo + workflow (release-please.yml).
   publish-npm:
     needs: [release-please, build-and-upload]
-    if: ${{ needs.release-please.outputs.release_created }}
+    # always(): publish whatever targets reached the release even if one build
+    # leg failed. The generator is partial-matrix-tolerant (only present targets
+    # are pinned in optionalDependencies) and fails loudly if nothing built.
+    if: ${{ always() && needs.release-please.outputs.release_created }}
     runs-on: ubuntu-latest
     permissions:
       contents: read
@@ -149,7 +152,9 @@ jobs:
 
   update-homebrew-formula:
     needs: [release-please, build-and-upload]
-    if: ${{ needs.release-please.outputs.release_created }}
+    # always(): the formula only needs the 4 darwin/linux-gnu assets, so a musl
+    # build failure shouldn't block it. Fails on its own if a core asset is missing.
+    if: ${{ always() && needs.release-please.outputs.release_created }}
     runs-on: ubuntu-latest
 
     steps:
@@ -180,14 +185,17 @@ jobs:
           VERSION=${{ needs.release-please.outputs.tag_name }}
           VERSION_NO_V=${VERSION#v}
 
-          # Download checksums
-          curl -L -o darwin-x64.sha256 \
+          # Download checksums. -f makes curl fail (non-zero) on a 404 instead of
+          # writing an HTML error page into the .sha256 file — so when a core
+          # target is missing under always(), this job hard-fails rather than
+          # baking a corrupt checksum into the formula.
+          curl -fLsS -o darwin-x64.sha256 \
             "https://github.com/${{ github.repository }}/releases/download/${VERSION}/csp-darwin-x64.sha256"
-          curl -L -o darwin-arm64.sha256 \
+          curl -fLsS -o darwin-arm64.sha256 \
             "https://github.com/${{ github.repository }}/releases/download/${VERSION}/csp-darwin-arm64.sha256"
-          curl -L -o linux-x64.sha256 \
+          curl -fLsS -o linux-x64.sha256 \
             "https://github.com/${{ github.repository }}/releases/download/${VERSION}/csp-linux-x64.sha256"
-          curl -L -o linux-arm64.sha256 \
+          curl -fLsS -o linux-arm64.sha256 \
             "https://github.com/${{ github.repository }}/releases/download/${VERSION}/csp-linux-arm64.sha256"
 
           # Extract checksums

.github/workflows/release-rust.yml

@@ -74,12 +74,36 @@ jobs:
       - name: Add target
         run: rustup target add ${{ matrix.target }}
 
-      - name: Install musl tools
+      # The musl target pulls C/C++ deps (esaxx-rs C++ via tokenizers, onig/zstd
+      # C) but musl-tools only ships musl-gcc, not musl-g++, so esaxx-rs fails to
+      # build. cargo-zigbuild uses zig as a full C/C++ cross toolchain (clang +
+      # musl + libc++), which builds the whole native set. zig is installed from
+      # the official tarball, so no extra pinned third-party action is needed.
+      - name: Set up cargo-zigbuild (musl)
         if: ${{ endsWith(matrix.target, '-musl') }}
-        run: sudo apt-get update && sudo apt-get install -y musl-tools
+        run: |
+          ZIG_VERSION=0.13.0
+          # Zig signs releases with minisign (not SHA checksums). Verify the
+          # tarball against the official ziglang.org public key before extracting
+          # and executing it, so a compromised mirror/MITM can't inject a binary.
+          ZIG_PUBKEY="RWSGOq2NVecA2UPNdBUZykf1CCb147pkmdtYxgb3Ti+JO/wCYvhbAb/U"
+          TARBALL="zig-linux-x86_64-${ZIG_VERSION}.tar.xz"
+          sudo apt-get update && sudo apt-get install -y minisign
+          curl -fsSLO "https://ziglang.org/download/${ZIG_VERSION}/${TARBALL}"
+          curl -fsSLO "https://ziglang.org/download/${ZIG_VERSION}/${TARBALL}.minisig"
+          minisign -Vm "${TARBALL}" -P "${ZIG_PUBKEY}"
+          tar -xJf "${TARBALL}" -C "$RUNNER_TEMP"
+          echo "$RUNNER_TEMP/zig-linux-x86_64-${ZIG_VERSION}" >> "$GITHUB_PATH"
+          cargo install --locked cargo-zigbuild --version '^0.19'
 
       - name: Build release binary
-        run: cargo build --release --locked -p csp-cli --target ${{ matrix.target }}
+        shell: bash
+        run: |
+          if [[ "${{ matrix.target }}" == *-musl ]]; then
+            cargo zigbuild --release --locked -p csp-cli --target "${{ matrix.target }}"
+          else
+            cargo build --release --locked -p csp-cli --target "${{ matrix.target }}"
+          fi
 
       - name: Stage asset (unix)
         if: ${{ !startsWith(matrix.os, 'windows') }}
@@ -104,9 +128,11 @@ jobs:
             ${{ matrix.asset }}
             ${{ matrix.asset }}.sha256
 
+  # Resilient by design: runs even if some build legs failed (always()), so the
+  # targets that did build still reach the release. Fails only if NOTHING built.
   upload-release-assets:
     needs: build
-    if: ${{ inputs.tag != '' }}
+    if: ${{ always() && inputs.tag != '' }}
     runs-on: ubuntu-latest
     permissions:
       contents: write
@@ -119,8 +145,14 @@ jobs:
       - name: Prepare release assets
         run: |
           mkdir -p release
-          find artifacts -type f -exec cp {} release/ \;
-          ls -lh release/
+          find artifacts -type f -exec cp {} release/ \; 2>/dev/null || true
+          count=$(find release -type f | wc -l | tr -d ' ')
+          echo "staged $count asset file(s):"
+          ls -lh release/ || true
+          if [ "$count" -eq 0 ]; then
+            echo "::error::no built assets to upload — every build leg failed" >&2
+            exit 1
+          fi
 
       - name: Upload to release
         env: