Implement multi-platform build system with pure Go support

- Introduced a comprehensive build system that supports multiple platforms (Linux, macOS, Windows, Android) using pure Go builds (`CGO_ENABLED=0`).
- Updated all build and test scripts to ensure compatibility with the new purego approach, allowing for dynamic loading of `libsecp256k1` at runtime.
- Added detailed documentation on the build process, platform detection, and deployment options.
- Enhanced CI/CD workflows to automate builds for all supported platforms and include necessary libraries in releases.
- Updated `.gitignore` to exclude build output files.
- Created new documentation files for deployment and multi-platform build summaries.

scripts/benchmark.sh

@@ -30,8 +30,14 @@ RUN_DIR="${REPORTS_DIR}/run_${TIMESTAMP}"
 # Ensure the benchmark binary is built
 BENCHMARK_BIN="${REPO_ROOT}/cmd/benchmark/benchmark"
 if [[ ! -x "$BENCHMARK_BIN" ]]; then
-    echo "Building benchmark binary..."
-    go build -o "$BENCHMARK_BIN" "$REPO_ROOT/cmd/benchmark"
+    echo "Building benchmark binary (pure Go + purego)..."
+    cd "$REPO_ROOT/cmd/benchmark"
+    CGO_ENABLED=0 go build -o "$BENCHMARK_BIN" .
+    # Copy libsecp256k1.so if available (runtime optional)
+    if [[ -f "$REPO_ROOT/pkg/crypto/p8k/libsecp256k1.so" ]]; then
+        cp "$REPO_ROOT/pkg/crypto/p8k/libsecp256k1.so" "$(dirname "$BENCHMARK_BIN")/"
+    fi
+    cd "$REPO_ROOT"
 fi
 
 # Create output directory