fix: Remove unused variable warning and add release build script

- Fix unused `project_path` parameter warning in make_executable()
- Add build-release.sh for automated binary packaging
- Update .gitignore to exclude release artifacts
- Support cross-compilation for Linux and Windows binaries

Release artifacts are now built with ./build-release.sh and uploaded
to Gitea releases separately, keeping the git repo clean.

build-release.sh

@@ -0,0 +1,80 @@
+#!/bin/bash
+# Build release binaries for distribution
+# This script builds both Linux and Windows binaries (cross-compile)
+# 
+# For Windows-only builds, use build-release.ps1 on Windows
+# For Linux-only builds, comment out the Windows section below
+
+set -e
+
+VERSION=${1:-$(git describe --tags --always)}
+RELEASE_DIR="release-artifacts"
+
+echo "Building Weevil $VERSION release binaries..."
+echo ""
+
+# Clean previous artifacts
+rm -rf "$RELEASE_DIR"
+mkdir -p "$RELEASE_DIR"
+
+# Build Linux binary (optimized)
+echo "Building Linux x86_64 binary..."
+cargo build --release
+strip target/release/weevil
+
+# Package Linux binary
+echo "Packaging Linux binaries..."
+cd target/release
+tar -czf "../../$RELEASE_DIR/weevil-${VERSION}-linux-x86_64.tar.gz" weevil
+zip -q "../../$RELEASE_DIR/weevil-${VERSION}-linux-x86_64.zip" weevil
+cd ../..
+
+# Build Windows binary (cross-compile)
+echo ""
+echo "Building Windows x86_64 binary..."
+
+# Check if Windows target is installed
+if ! rustup target list | grep -q "x86_64-pc-windows-gnu (installed)"; then
+    echo "Installing Windows target..."
+    rustup target add x86_64-pc-windows-gnu
+fi
+
+# Check if MinGW is installed
+if ! command -v x86_64-w64-mingw32-gcc &> /dev/null; then
+    echo "Warning: MinGW not found. Install with: sudo apt install mingw-w64"
+    echo "Skipping Windows build."
+else
+    cargo build --release --target x86_64-pc-windows-gnu
+    x86_64-w64-mingw32-strip target/x86_64-pc-windows-gnu/release/weevil.exe
+    
+    # Package Windows binary
+    echo "Packaging Windows binary..."
+    cd target/x86_64-pc-windows-gnu/release
+    zip -q "../../../$RELEASE_DIR/weevil-${VERSION}-windows-x86_64.zip" weevil.exe
+    cd ../../..
+fi
+
+# Generate checksums
+echo ""
+echo "Generating checksums..."
+cd "$RELEASE_DIR"
+sha256sum * > SHA256SUMS
+cd ..
+
+# Display results
+echo ""
+echo "═══════════════════════════════════════════════════════════"
+echo "   ✓ Release artifacts built successfully!"
+echo "═══════════════════════════════════════════════════════════"
+echo ""
+echo "Artifacts in $RELEASE_DIR/:"
+ls -lh "$RELEASE_DIR"
+echo ""
+echo "Checksums:"
+cat "$RELEASE_DIR/SHA256SUMS"
+echo ""
+echo "Upload these files to your Gitea release:"
+echo "  1. Go to: Releases → $VERSION → Edit Release"
+echo "  2. Drag and drop files from $RELEASE_DIR/"
+echo "  3. Save"
+echo ""