Install afl in zig fuzz

actions/cairn-zig-fuzz/action.yml

@@ -1,5 +1,5 @@
 name: 'Cairn Zig Fuzz (AFL++)'
-description: 'Build and run AFL++ fuzz targets, report crashes to Cairn. Each line in zig_build_args is a separate target.'
+description: 'Install AFL++, then build and run AFL++ fuzz targets, reporting crashes to Cairn. Each line in zig_build_args is a separate target.'
 
 inputs:
   cairn_server:
@@ -51,12 +51,15 @@ inputs:
 runs:
   using: 'composite'
   steps:
+    - name: Setup AFL++
+      uses: mattnite/cairn/actions/setup-afl@main
+
     - name: Check prerequisites
       shell: sh
       run: |
         set -eu
         command -v zig >/dev/null 2>&1 || { echo "ERROR: zig not found in PATH. Install Zig before using this action (e.g. https://codeberg.org/mlugg/setup-zig@v2)."; exit 1; }
-        command -v afl-cc >/dev/null 2>&1 || { echo "ERROR: afl-cc not found in PATH. Install AFL++ before using this action (e.g. mattnite/cairn/actions/setup-afl@main)."; exit 1; }
+        command -v afl-cc >/dev/null 2>&1 || { echo "ERROR: afl-cc not found in PATH after setup-afl step."; exit 1; }
         echo "zig $(zig version), afl-cc found"
 
     - name: Setup Cairn CLI