Add CI workflow, run tests per-architecture before release

Separate ci.yml runs on push/PR. In release.yml, a ci job runs
zig build, zig tests, and elixir tests on each architecture target.
NIF builds only start after all ci jobs pass.

Pipeline: ci (x86_64-linux + aarch64-macos) → build_nif → release

Author: bcardarella

.github/workflows/ci.yml

@@ -0,0 +1,43 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  test:
+    strategy:
+      matrix:
+        include:
+          - os: ubuntu-latest
+          - os: macos-latest
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: mlugg/setup-zig@v2
+        with:
+          version: 0.15.2
+
+      - name: Build Zig library
+        run: zig build -Doptimize=ReleaseFast
+
+      - name: Run Zig tests
+        run: zig build test
+
+      - name: Set up Erlang/Elixir
+        uses: erlef/setup-beam@v1
+        with:
+          otp-version: "27"
+          elixir-version: "1.17"
+
+      - name: Run Elixir tests
+        env:
+          TAILWIND_COMPILER_PATH: "true"
+        run: |
+          mix local.hex --force
+          mix local.rebar --force
+          mix deps.get
+          mix test

.github/workflows/release.yml

@@ -9,14 +9,21 @@ permissions:
   contents: write
 
 jobs:
-  test:
-    name: Test
-    runs-on: ubuntu-22.04
+  ci:
+    name: CI (${{ matrix.target }})
+    runs-on: ${{ matrix.runner }}
+    strategy:
+      fail-fast: true
+      matrix:
+        include:
+          - target: x86_64-linux
+            runner: ubuntu-22.04
+          - target: aarch64-macos
+            runner: macos-15
     steps:
       - uses: actions/checkout@v4
 
-      - name: Install Zig
-        uses: mlugg/setup-zig@v2
+      - uses: mlugg/setup-zig@v2
         with:
           version: 0.15.2
 
@@ -43,7 +50,7 @@ jobs:
 
   build_nif:
     name: Build NIF (${{ matrix.target }})
-    needs: test
+    needs: ci
     runs-on: ${{ matrix.runner }}
     strategy:
       fail-fast: true
@@ -134,7 +141,7 @@ jobs:
 
   release:
     name: Create Release
-    needs: [test, build_nif]
+    needs: build_nif
     runs-on: ubuntu-latest
     steps:
       - name: Download all artifacts