add fuzz tests

.github/workflows/fuzz.yml

@@ -0,0 +1,18 @@
+name: Fuzz
+on:
+  schedule:
+    - cron: '0 21 * * *' # run at 9 PM UTC
+  # Allow manual runs
+  workflow_dispatch:
+jobs:
+  fuzz:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        target: [fuzz, fuzz_tls]
+    name: ${{ matrix.target }}
+    steps:
+    - uses: actions/checkout@v4
+      with: { fetch-depth: 2 }
+    - run: make -C test ${{ matrix.target }}