chore: add install scripts

scripts/install.ps1

@@ -0,0 +1,46 @@
+$ErrorActionPreference = 'Stop'
+
+$ARCH = $env:PROCESSOR_ARCHITECTURE
+
+switch -Regex ($ARCH) {
+    "AMD64" { $ARCH_NAME = "x86_64" }
+    "x86"   { $ARCH_NAME = "i686" }
+    "ARM64" { $ARCH_NAME = "aarch64" }
+    default {
+        Write-Host "❌ Error: Unsupported Architecture: $ARCH"
+        exit 1
+    }
+}
+
+$BASE_URL = "https://fast-down-update.s121.top/cli/download/latest"
+$DOWNLOAD_URL = "$BASE_URL/windows/$ARCH_NAME"
+
+# Idiomatic Windows user-level installation path
+$INSTALL_DIR = "$env:LOCALAPPDATA\Programs\fast-down"
+$BIN_NAME = "fast-down.exe"
+$TMP_FILE = [System.IO.Path]::GetTempFileName()
+
+Write-Host "Downloading $DOWNLOAD_URL ..."
+try {
+    Invoke-WebRequest -Uri $DOWNLOAD_URL -OutFile $TMP_FILE -UseBasicParsing
+} catch {
+    Write-Host "❌ Error: Failed to download the file."
+    Remove-Item -Path $TMP_FILE -ErrorAction SilentlyContinue
+    exit 1
+}
+
+if (-not (Test-Path -Path $INSTALL_DIR)) {
+    New-Item -ItemType Directory -Force -Path $INSTALL_DIR | Out-Null
+}
+
+Move-Item -Path $TMP_FILE -Destination "$INSTALL_DIR\$BIN_NAME" -Force
+
+Write-Host "🎉 Installed to $INSTALL_DIR\$BIN_NAME"
+
+# Check if the install directory is in the PATH
+if (($env:PATH -split ';') -notcontains $INSTALL_DIR) {
+    Write-Host "⚠️ Note: You need to add $INSTALL_DIR to your PATH environment variable."
+    Write-Host "   You can do this by searching for 'Edit environment variables for your account' in the Start menu."
+} else {
+    Write-Host "🚀 You can now run 'fast-down' from your terminal!"
+}

scripts/install.sh

@@ -0,0 +1,57 @@
+#!/bin/bash
+
+set -e
+
+OS="$(uname -s)"
+ARCH="$(uname -m)"
+
+case "$OS" in
+    Linux*)  OS_NAME="linux" ;;
+    Darwin*) OS_NAME="macos" ;;
+    *)       echo "❌ Error: Unsupported OS: $OS. This script only supports Linux and macOS."; exit 1 ;;
+esac
+
+case "$ARCH" in
+    x86_64|amd64)        ARCH_NAME="x86_64" ;;
+    i386|i686|x86)       ARCH_NAME="i686" ;;
+    aarch64|arm64|armv8) ARCH_NAME="aarch64" ;;
+    *)                   echo "❌ Error: Unsupported Architecture: $ARCH"; exit 1 ;;
+esac
+
+if [ "$OS_NAME" = "macos" ]; then
+    if [ "$ARCH_NAME" != "aarch64" ] && [ "$ARCH_NAME" != "x86_64" ]; then
+        echo "❌ Error: Unsupported architecture for macOS: $ARCH_NAME. Only aarch64 and x86_64 are supported."
+        exit 1
+    fi
+fi
+
+BASE_URL="https://fast-down-update.s121.top/cli/download/latest"
+DOWNLOAD_URL="${BASE_URL}/${OS_NAME}/${ARCH_NAME}"
+
+INSTALL_DIR="$HOME/.local/bin"
+BIN_NAME="fast-down"
+TMP_FILE=$(mktemp)
+
+# 5. Download the binary
+echo "Downloading $DOWNLOAD_URL ..."
+if command -v curl >/dev/null 2>&1; then
+    curl -# -L -o "$TMP_FILE" "$DOWNLOAD_URL"
+elif command -v wget >/dev/null 2>&1; then
+    wget -q --show-progress -O "$TMP_FILE" "$DOWNLOAD_URL"
+else
+    echo "❌ Error: curl or wget is required to download the file."
+    rm -f "$TMP_FILE"
+    exit 1
+fi
+
+chmod +x "$TMP_FILE"
+mkdir -p "$INSTALL_DIR"
+mv "$TMP_FILE" "$INSTALL_DIR/$BIN_NAME"
+
+echo "🎉 Installed to $INSTALL_DIR/$BIN_NAME"
+
+if [[ ":$PATH:" != *":$HOME/.local/bin:"* ]]; then
+    echo "⚠️ Note: You may need to add $INSTALL_DIR to your PATH in your ~/.bashrc or ~/.zshrc."
+else
+    echo "🚀 You can now run '$BIN_NAME' from your terminal!"
+fi