Unify zip duplicate handling

Co-authored-by: Valorith <76063792+Valorith@users.noreply.github.com>

.github/workflows/build.yaml

@@ -30,7 +30,7 @@ jobs:
             echo "ccache not found in container; installing."
             apt-get update -qq
             DEBIAN_FRONTEND=noninteractive apt-get install -y -qq ccache
-            command -v ccache >/dev/null 2>&1
+            command -v ccache >/dev/null 2>&1 || { echo "ccache install failed"; exit 1; }
           fi
 
       - name: Mark workspace safe

.github/workflows/release.yaml

@@ -83,11 +83,9 @@ jobs:
           }
 
           # Add all executable files (excluding tests)
-          ZIP_CONTENTS="$(unzip -Z1 eqemu-server-linux-x64.zip 2>/dev/null || true)"
           for f in *; do
             if [ -f "$f" ] && [ -x "$f" ] && [ "$f" != "tests" ]; then
-              zip_add "$f"
-              ZIP_CONTENTS="${ZIP_CONTENTS}${f}"$'\n'
+              zip_add_unique "$f"
             fi
           done