chore: import upstream snapshot with attribution

.github/actions/ccache-clear/action.yml

@@ -0,0 +1,22 @@
+name: "ccache-clear"
+description: "Delete all GitHub Actions caches matching a key prefix"
+inputs:
+  key:
+    description: "Cache key prefix to match and delete"
+    required: true
+
+runs:
+  using: "composite"
+  steps:
+    - name: Clear caches
+      shell: bash
+      run: |
+        CACHES=$(gh cache list --key "ccache-${{ inputs.key }}" --json id,key --jq '.[] | "\(.id) \(.key)"' 2>/dev/null)
+        if [ -z "$CACHES" ]; then
+          echo "No caches found with key prefix: ${{ inputs.key }}"
+          exit 0
+        fi
+        while read -r id key; do
+          echo "Deleting cache: $id ($key)"
+          gh cache delete "$id"
+        done <<< "$CACHES"