Add GitHub Actions workflow for benchmarking GC performance

.github/workflows/benchmark-gc.yml

@@ -0,0 +1,45 @@
+# TODO: Add full length action hashes for all actions
+
+name: Benchmark GC Performance
+
+on:
+  push:
+    branches: [ main, master ]
+  pull_request:
+    branches: [ main, master ]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  actions: write
+
+jobs:
+  benchmark:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Go
+      uses: actions/setup-go@v4
+      with:
+        go-version: '1.25'
+
+    - name: Cache Go modules
+      uses: actions/cache@v3
+      with:
+        path: |
+          ~/.cache/go-build
+          ~/go/pkg/mod
+        key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
+        restore-keys: |
+          ${{ runner.os }}-go-
+
+    - name: Install dependencies
+      run: go mod download
+
+    - name: Run benchmark (standard GC)
+      run: make bench
+
+    - name: Run benchmark (experimental GC)
+      run: make bench-experimental